MOHAMEDAMINE Ghebouli

عبد الغاني رحال , عبد الغاني رحال, عبد الغاني رحال

Contribution à la maîtrise et à l’optimisation des propriétés des couches minces d’oxydes métalliques : analyse, caractérisation et applications

Ali-Saoucha Salim

Study, fabrication and characterization of thin films for CZTS solar cells

Younes Naceur

Etude des propriétés structurales, électroniques optiques et thermodynamiques des semi-conducteurs de type A2MX6 par la méthode ab-initio.

سعدي زهية

Contribution à l'étude des propriétes physique de la famille pérovskites en utilisant la théorie du pseudo-potentiel

Radja Nour El houda , Ben Salem Souhyla

Caractirisation structurale, électronique et optique des semi-conducteurs CdTe et CdS pour des applications dans les cellules photovoltaiques

Larbi Radhia

Etude des propriétes structurales, électroniques et optiques des semiconducteurs CdS et ZnO pour des application photovoltaiques

Zeghad Aldjia

Etude des propriétes structurales, électroniques et optiques des semiconducteurs GaX (X P, As et Sb) par la méthode Ab-initio

بن هدوقة ايمان

Etude structural et electronique des semi-conducteurs ZnS et ZnO pour des applications photovoltaique

علالي بلال

Etude structural , electronique et élastiques des composées BaIrO3 et BaBbO3 par Ab-initio

بن زروق نبيل

Etude par simulation desv propriétes structurales et électroniques des semi-conducteurs

لعويجي حورية

Etude des propriétés structurales, élastique et électroniques du semi-conducteur AlP par la méthode ab-initiotio

بن ساعد شريف

Etude des propriétés structurales, élastique et électroniques des semi-conducteurs par la méthode Ab-Initio

The present work involves numerical modeling of the Forming Limit Diagram (FLD) in a heterogeneous weld bead generated by FSW of two aluminum alloys (AA2139-T8 and AA7020-T651) through Nakazima test simu- lation using Abaqus software and the second derivative of the large deformation criterion to locate the necking. A concept is proposed to determine the FLD of welded bi-material sheet by the extrapolation method and the direct method. In the extrapolation method, FLDs have been predetermined for each of the seven weld zones and extrapolated into FSW configuration. In the direct method, a simplified geometrical model limiting FSW zones is used to determine the FLD for the global FSW bi-material assembled sheet. Results show that the extrapolation method is slightly lower, they agree well with the direct method that shows acceptable values of the major and minor strains, particularly in the expansion region, thus providing good indicative strain values during drawing. The direct method was found to provide a more conservative and realistic prediction of forming limits, especially in strain paths representative of deep-drawing operations, where failure is governed by the material behavior in the expansion region. It was also observed that the heat affected zones govern the onset of localized necking, while the base material AA2139-T8 exhibits the highest formability level among all weld zones. This is the first study to compare two different simulation approaches for FLD extraction in a fully heterogeneous FSW weld bead. The proposed methodology provides a practical numerical framework for predicting the formability of dissimilar aluminum welded sheets and can assist in the design and optimization of lightweight components in the aerospace, automotive, and structural industries.

Citation

MohamedAmine GHEBOULI , , (2025-12-30), Comparative Study of Extrapolation and Direct Methods for FLD Prediction in Friction Stir Welded Aluminum Sheets, Materials Today Communications, Vol:50, Issue:, pages:114599, Elsevier

We report a detailed first-principles investigation of the structural, electronic, optical, and thermoelectric properties of CaXO₃ (X = Si, Ge, Ti) perovskites using density functional theory with both GGA and mBJ-GGA functionals. Optimized lattice constants CaSiO₃ (3.6073 Å), CaGeO₃ (3.7775 Å), CaTiO₃ (3.8811 Å) reflect systematic variation with B-site cation size. Energy–volume optimization confirms structural stability, while phonon dispersions show no imaginary frequencies, indicating dynamical stability. All compounds are indirect-gap semiconductors, with band gaps strongly dependent on the computational method. Optical absorption edges span the UV to near-visible range, suggesting promise for optoelectronic and photovoltaic applications. Thermoelectric transport analysis at 400 K reveals favorable Seebeck coefficients and electrical conductivity profiles. Electron density difference mapping for CaGeO₃ highlights mixed ionic–covalent bonding in Ge–O linkages and primarily ionic Ca–O interactions. These integrated findings demonstrate the tunable potential of CaXO₃ perovskites for energy conversion and advanced optical devices

Citation

MohamedAmine GHEBOULI , , (2025-12-10), Structural, electronic, optical, and thermoelectric properties of CaXO₃ (X= Si, Ge, Ti) perovskite for photovoltaics and optical devices, Scientific Reports, Vol:15, Issue:, pages:43569, Nature Publishing Group UK

The objective of this work is to explore the optical, morphological, and photocatalytic properties of two inno- vative conjugated copolymers: poly(2,5-diyl pyrrole) [3-nitrobenzylidene] (PP3NB) and poly(2,5-diyl pyrrole) [2,4-dinitrobenzylidene] (PPDNB). These copolymers were synthesized by condensation, and their thin films were prepared by dip-coating. This is followed by characterization by UV–Vis spectroscopy, scanning electron microscopy (SEM), and cyclic voltammetry (CV). Optical analysis revealed a broad absorption in the visible spectrum, with band gaps of approximately 2.1 eV for PP3NB and 1.98 eV for PPDNB. Morphological charac- terization revealed the formation of uniform and adherent films to the substrate, with tunable surface roughness, which influences the charge transport characteristics. Electrochemical calculations established the HOMO- –LUMO energy levels, showing good alignment with typical donor–acceptor systems. The effective masses of charge carriers, derived from the HOMO–LUMO band gaps and conjugation lengths, were 0.00635 mₑ for PP3NB and 0.00596 mₑ for PPDNB, indicating improved charge mobility. Based on the band edge positions, the pho- tocatalytic potential evaluation suggests that PPDNB demonstrates superior capabilities for reduction reactions, especially in hydrogen evolution and CO₂ reduction, while PP3NB excels in oxidation processes. These results highlight the versatility and efficiency of pyrrole-nitrobenzylidene copolymers for renewable energy conversion and environmental remediation applications, highlighting their potential in organic solar cells, photocatalysis, and water-splitting technologies

Citation

MohamedAmine GHEBOULI , , (2025-12-01), 2D Materials unleashed: Pyrrole-nitrobenzylidene copolymers for advanced photocatalysis for water-splitting technologies, Molecular Catalysis, Vol:587, Issue:, pages:115473, Elsevier

Polyoxymethylene (POM) is a semi-crystalline thermoplastic renowned for its outstanding mechanical strength, wear resistance, and dimensional stability. This study examines the fracture mechanics and mechanical behavior of POM under large deformations using both experimental and numerical approaches. Tensile tests on notched and unnotched specimens reveal a transition from linear elasticity to nonlinear viscoelastic and plastic behavior, with failure mechanisms primarily governed by cavitation and fibrillation. Fracture toughness is assessed using the J-integral method, which demonstrates a strain rate-dependent response. Load-displacement curves show that higher strain rates lead to increased stress thresholds, followed by softening, an extended plateau, and subsequent hardening. Thermal analysis confirms POM’s high crystallinity (~40 %) and stability at elevated temperatures. Numerical simulations in ABAQUS validate the experimental findings, emphasizing the role of stress triaxiality in crack propagation and failure mechanisms. The results highlight POM’s ductile fracture behavior and provide valuable insights for optimizing its performance in structural and industrial applications. Future research should focus on refining predictive models that integrate plastic deformation and damage evolution to further enhance POM’s reliability under extreme conditions.

Citation

MohamedAmine GHEBOULI , , (2025-11-28), Mechanical and Fracture Analysis of Polyoxymethylene for Industrial, Aerospace and Automotive Structures, Materials Today Communications, Vol:50, Issue:, pages:114411, Elsevier

Lead-free double perovskites have emerged as promising alternatives to conventional lead halide perovskites for optoelectronic applications due to their enhanced stability and reduced toxicity. In this study, we systematically investigate the structural, electronic, and optical properties of K₂AgSbBr₆ double perovskite and its doped variants through density functional theory (DFT) calculations. We examine three strategic doping schemes: Cu⁺ substitution at the Ag⁺ site, Bi³⁺ substitution at the Sb³⁺ site, and I⁻ substitution at the Br⁻ site. Our results reveal that Cu⁺ and I⁻ doping significantly narrow the band gap from 0.554 eV to 0.444 eV and 0.440 eV, respectively, enhancing visible light absorption, while Bi³⁺ doping widens the gap to 1.547 eV, making it suitable for UV applications. Structural analysis shows that Cu⁺ doping leads to lattice contraction with increased mechanical stiffness, while I⁻ substitution causes substantial lattice expansion with reduced bulk modulus, potentially facilitating ion migration. Thermodynamic and mechanical stability analyses were performed and confirmed that all pristine and doped systems are dynamically and mechanically stable, ensuring their viability for practical applications. Optical property analysis reveals enhanced polarizability and absorption coefficients for I⁻-doped systems, while maintaining favorable dielectric properties across all variants. These results explicitly connect the electronic structure modifications to the observed optical behavior, offering a clear design strategy for targeted optoelectronic functionalities. Importantly, the calculated band gaps and optical responses identify Cu⁺- and I⁻-doped K₂AgSbBr₆ as strong candidates for near-infrared and broadband photodetectors, while Bi³⁺-doped K₂AgSbBr₆ is more suitable for tandem solar cells and UV optoelectronic devices. This explicit mapping of material properties to applications provides actionable guidance for experimental synthesis and device prototyping, thereby bridging the gap between computational predictions and practical implementation.

Citation

MohamedAmine GHEBOULI , , (2025-11-18), Electronic and optical properties of lead-free K₂AgSbBr₆ double perovskite tuned by doping elements Cu⁺, Bi³⁺, and I⁻, Scientific Reports, Vol:15, Issue:1, pages:40362, Scientific Reports

The morphological evolution of poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojunction active layers during solvent evaporation represents a critical determinant of organic photovoltaic device performance. This study employs coarse-grained molecular dynamics simulations based on the Martini 3.0 force field to investigate the structural reorganization of P3HT: PCBM: chlorobenzene ternary systems under controlled evaporation conditions. Two distinct solvent removal protocols (1% and 3.75% chlorobenzene removal per step) were systematically evaluated to elucidate their impact on donor-acceptor phase separation and interfacial morphology. The simulation system comprised 75 P3HT chains (degree of polymerization = 48), 526 PCBM molecules, and 2500 chlorobenzene molecules within a 15 × 15 × 44 nm³ periodic simulation box. Structural analysis through radial distribution functions, density profiles, and cluster analysis revealed significant differences in phase separation behavior between the two evaporation rates. Slower evaporation (1% removal) promoted enhanced P3HT chain ordering and more favorable donor-acceptor interfacial contact, while rapid evaporation (3.75% removal) led to kinetically trapped morphologies with reduced structural order. The findings provide molecular-level insights into processing-structure relationships in organic photovoltaic active layers and offer guidance for optimizing solution-processing conditions. Furthermore, the quantitative comparison between slow and fast solvent evaporation provides predictive insights that can guide experimental protocols and bridge the gap between computational modeling and device fabrication.

Citation

MohamedAmine GHEBOULI , , (2025-11-02), Solvent driven morphology for molecular level insights into enhancing organic solar cell performance in P3HT-PCBM bulk heterojunctions, Journal of Polymer Research, Vol:32, Issue:11, pages:1-8, Springer Netherlands

This research paper presents a comprehensive study of Cu2O-based heterojunction solar cells, focusing on the effects of bath temperature, absorber layer thickness, and defect density on cell efficiency. Cu2O thin films were electrochemically deposited at various bath temperatures (40–80 ◦C), and their structural and optical properties were investigated. Performance simulations using SCAPS software revealed that the optimal Cu2O layer thickness is 4 μm, yielding a conversion efficiency of 12.1 %. Under optimal conditions (bath temperature 60 ◦C and absorber thickness 4 μm), the device achieved a simulated efficiency of 12.6 %. Results demonstrated that moderate acceptor density (1017 cm3) and low defect density (1014 cm3) lead to significant improvements in cell efficiency. This study provides valuable insights for developing high-efficiency Cu2O/CdS/ZnO solar cells, emphasizing the importance of controlling deposition parameters and layer design for enhanced performance of copper oxide-based photovoltaics.

Citation

MohamedAmine GHEBOULI , , (2025-11-01), Experimental and simulation study of Cu2O-based heterojunction solar cells: Effects of bath temperature, layer thickness and defect density, Solid State Communications, Vol:405, Issue:, pages:116135, Pergamon

This research paper presents a comprehensive study of Cu2O-based heterojunction solar cells, focusing on the effects of bath temperature, absorber layer thickness, and defect density on cell efficiency. Cu2O thin films were electrochemically deposited at various bath temperatures (40–80 °C), and their structural and optical properties were investigated. Performance simulations using SCAPS software revealed that the optimal Cu2O layer thickness is 4 μm, yielding a conversion efficiency of 12.1 %. Under optimal conditions (bath temperature 60 °C and absorber thickness 4 μm), the device achieved a simulated efficiency of 12.6 %. Results demonstrated that moderate acceptor density (1017 cm−3) and low defect density (1014 cm−3) lead to significant improvements in cell efficiency. This study provides valuable insights for developing high-efficiency Cu2O/CdS/ZnO solar cells, emphasizing the importance of controlling deposition parameters and layer design for enhanced performance of copper oxide-based photovoltaics.

Citation

Idris BOUCHAMA , MohamedAmine GHEBOULI , Abdelghani Rahal, Brahim Ghebouli, Fatmi Messaoud, Talal Mohamed Althagafi, Samah Boudour, , (2025-11-01), Experimental and simulation study of Cu2O-based heterojunction solar cells: Effects of bath temperature, layer thickness and defect density, Solid State Communications, Vol:405, Issue:1, pages:116135, Elsevier

First-principle calculations were conducted using the Wien2k code with the GGA, mBJ-GGA, and PBE0 (HSE06) functionals. The optimized lattice constants for the cubic unit cells of CaFeO3 and BaFeO3 closely match the experimental values of 3.77 Å and 3.971 Å, respectively. The band structures and densities of states obtained with the mBJ-GGA method, along with the integer magnetic moment of 4 µB per unit cell, confirm the half-metallic nature of BaFeO3 and CaFeO3 in the spin-up channel. Both compounds, characterized by high symmetry, are more stable in the ferromagnetic half-metallic phase. For mBJ-GGA and YS-PBE0(HSE06) functionals, the materials under study are spin-gapless semiconductors. Hybridization of O-2p orbital with Fe-3d state in the upper valence band for spin-upmakes BaFeO3and CaFeO3as metallic materials. BaFeO3 and CaFeO3 exhibit large absorption coefficient 350 × 104 cm−1 and 500 × 104 cm−1 in the ultraviolet range, which can be attributed to the infrared phonon mode. The observed refractive index below 1 at the ultraviolet energy is a sign that these materials become superluminal. Furthermore, phonon dispersion calculations revealed the absence of imaginary frequencies across the Brillouin zone, confirming the dynamical stability of both perovskites and reinforcing their suitability for spintronic and optoelectronic applications.

Citation

MohamedAmine GHEBOULI , , (2025-10-23), Ferromagnetic and half metallic properties of BaFeO₃ and CaFeO₃ for spintronic applications, Scientific Reports, Vol:15, Issue:1, pages:37093, Nature Publishing Group UK

The structural, electronic, magnetic, thermal, and optical properties of the quaternary Heusler alloys FeCrTiM (where M = Al, As, Si) were investigated using first-principles density functional theory (DFT) calculations. The ground state is found to be the type-1 ferrimagnetic configuration. In addition, the calculated formation energies (− 1.63 eV for FeCrTiAl, − 1.048 eV for FeCrTiAs, and − 0.774 eV for FeCrTiSi) confirm that these compounds are thermodynamically stable relative to their elemental constituents, suggesting the possibility of experimental synthesis under suitable conditions. The calculated lattice constants and ground-state parameters for FeCrTiAs and FeCrTiAl are presented as theoretical predictions. Based on band structure analysis, FeCrTiAs and FeCrTiSi exhibit half-metallic ferrimagnetism at equilibrium, although near spin-gapless features may emerge under lattice distortions. This makes them promising candidates for spintronic applications. All studied compounds display half-metallic ferrimagnetism with total magnetic moments that follow the Slater-Pauling rule, increasing linearly with the number of valence electrons. The optical properties reveal high static dielectric constants and refractive indices, indicating potential applications in optoelectronic devices. Additionally, the thermoelectric performance of these materials was evaluated, with calculated Seebeck coefficients up to ~ 1.5 mV·K⁻1, electrical conductivity σ ≈ 3.5 × 10⁶ S·m⁻1, electronic thermal conductivity around 25 W·m⁻1·K⁻1, and a predicted figure of merit (ZT) close to 1 at 300 K. These combined results suggest that FeCrTiM (M = Al, As, Si) alloys are multifunctional materials with strong potential for use in high-performance energy conversion, optoelectronics, and spintronic devices.

Citation

MohamedAmine GHEBOULI , , (2025-10-01), Half-metallicity and spin-gapless semiconducting properties in fecrtim (M= Al, As, Si) quaternary heusler alloys for spintronic, thermoelectric and optoelectronic applications, Advanced Composites and Hybrid Materials, Vol:8, Issue:5, pages:366, Springer International Publishing

A comprehensive first-principles study of the structural, electronic, elastic, and thermodynamic properties of CdV₂O₄, MgV₂O₄, and ZnV₂O₄ spinel compounds has been performed using density functional theory (DFT) within the local density approximation (LDA). The calculations were carried out using the CASTEP Package. Our results show that all three compounds exhibit semiconducting behavior with complex electronic structures dominated by V 3d and O 2p states. The calculated lattice parameters demonstrate excellent agreement with experimental data, with deviations less than 3%. The bulk moduli follow the order ZnV₂O₄ (208.2 GPa) > MgV₂O₄ (174.2 GPa) > CdV₂O₄ (165.2 GPa), correlating inversely with the ionic radii of the A-site cations. Elastic properties analysis confirms mechanical stability for all compounds, with MgV₂O₄ showing the highest elastic anisotropy (A = 1.383). The pressure–volume relationships follow the Birch-Murnaghan equation of state, enabling accurate prediction of high-pressure behavior. Thermodynamic calculations reveal that heat capacities approach the classical Dulong-Petit limit at elevated temperatures, with Debye temperatures of 576.61 K, 615.04 K, and 716.91 K for CdV₂O₄, MgV₂O₄, and ZnV₂O₄, respectively. These findings provide fundamental insights into the structure–property relationships of vanadium-based spinel compounds for potential applications in electronic devices, high-pressure technologies, and thermal management systems.

Citation

MohamedAmine GHEBOULI , , (2025-10-01), Investigation of Structural, Electronic, Elastic and Thermodynamic Properties of AV2O4 (A = Cd, Mg, Zn) Spinel Compounds, Journal of Superconductivity and Novel Magnetism, Vol:38, Issue:5, pages:205, Springer US

This study investigated the synthesis and analysis of Co–Zn nanoferrites, specifically Co0.6Zn0.4Fe2O4, using the sol–gel method. The morphological, structural, and electrical properties of these ferrites were explored. The Co0.6Zn0.4Fe2O4 spinel ferrite was synthesized using metal nitrate reagents and ethylene glycol, followed by a series of heating and sintering processes. Rietveld-refined X-ray diffraction (XRD) confirmed the crystalline structure and phase purity, revealing a monophasic spinel structure. Scanning electron microscopy (SEM) analysis showed distinct grain agglomeration and porosity, indicating the material’s unique microstructure. Impedance measurements further characterized the optical and electrical properties. The electrical conductivity of Co0.6Zn0.4Fe2O4 demonstrated a thermally activated conduction process, adhering to Jonscher’s universal power law. The complex impedance analysis revealed thermally activated behavior, confirming the presence of relaxation processes influenced by temperature. Nyquist plots indicated the contributions of grains, grain boundaries, and electrodes to the electrical behavior. The complex electrical modulus and dielectric studies provided insights into the dielectric characteristics, confirming high space charge polarization at grain boundaries and low dielectric loss. These findings suggested that Co0.6Zn0.4Fe2O4 nanoferrites synthesized via the sol–gel method exhibited desirable electrical and structural properties, making them promising for various technological applications.

Citation

MohamedAmine GHEBOULI , , (2025-10-01), Dielectric and structural properties of Co0.6Zn0.4Fe2O4 nanoferrites: sol–gel synthesis, Journal of Sol-Gel Science and Technology, Vol:116, Issue:1, pages:16-33, Springer US

This study investigates the structural, electronic, mechanical, and thermodynamic properties of Li 3X compounds (where X represents nitro- gen, phosphorus, and arsenic) using first-principles calculations based on density functional theory. Calculations were performed using the QUANTUM ESPRESSO package within the generalized gradient approximation framework with DFT-D3 dispersion correction to account for van der Waals interactions. Results show systematic trends in the hexagonal crystal structure, with lattice parameters increasing and bulk modulus values decreasing significantly from Li3 N to Li 3P to Li 3As. Elastic constant analysis reveals decreasing values across all constants, with C13 showing the most dramatic reduction, indicating reduced mechanical coupling between axes. The B/G ratios (1.51, 1.17, and 1.17 for Li3 N, Li 3P, and Li3As, respectively) classify all three compounds as brittle materials according to Pugh’s criterion. Electronic structure analysis demonstrates a transition from predominantly ionic bonding in Li 3N to more covalent character in Li 3P and Li3As, manifested in decreasing bandgaps (1.1 eV to 0.7 eV to 0.65 eV) and increased orbital hybridization. Thermodynamic properties studied through the quasi-harmonic approximation show differences in vibrational energy, entropy (with Li 3As exhibiting the highest values), and isochoric heat capacity (approaching the Dulong–Petit limit at high temperatures). This study provides crucial insights into the relationship between atomic structure and physical properties of these compounds, thereby highlighting their potential in energy storage and thermoelectric applications.

Citation

MohamedAmine GHEBOULI , , (2025-09-01), Structural, electronic, and thermodynamic properties of Li3X (X= N, P, As) compounds for solid-state lithium-ion batteries, Journal of Vacuum Science & Technology A, Vol:43, Issue:5, pages:052801-1, AIP Publishing

This research aims to investigate the impact of doping the organic compound C16H10Br2O2 with various halogens (chlorine, fluorine, bromine, and iodine) on its structural, electronic, and optical properties. Modern computational simulation tools were employed to study the changes in molecular structure, charge distribution, and electron density upon the addition of each type of halogen. Additionally, the energy gap between molecular states was calculated, and the relative stability of the doped compounds was evaluated. The results revealed significant changes in the electronic and optical properties of the compound upon halogen doping. The type of halogen used was found to have a significant impact on these properties. The results indicate that some of the doped compounds possess promising properties for applications in optoelectronic devices, such as solar cells and organic light-emitting diodes.

Citation

MohamedAmine GHEBOULI , , (2025-08-01), Structural, Electronic, and Optical Properties of Halogen-Doped C16H10X2O2 (X = F, Cl, Br, I) Compounds for the Organic Electronics Applications, Physics of Metals and Metallography, Vol:126, Issue:8, pages:888-896, Pleiades Publishing

This study explores the Magnetic, Optical and thermoelectric properties of europium-doped Gallium Nitride (Eu:GaN) using the Full-Potential Linearized Augmented Plane Wave method within Density Functional Theory framework, employing the Modified Becke–Johnson method. By substituting a Gallium atom with a Europium atom in the hexagonal crystal structure of GaN with a nominal doping rate of 6%, characteristic electronic transitions and localized magnetic moments associated with Eu3+ ions were revealed through our calculations. Additionally, optical analysis revealed enhanced Absorption, particularly in the Ultraviolet region, while thermoelectric properties, calculated using the Boltz-TraP program, demonstrated significant enhancements in electrical conductivity and Power Factor up to 800 K. The figure of Merit reached 0.955 at room temperature. These findings highlight the potential of EuGaN for a range of applications, including use in optoelectronics such as ultraviolet detectors, LEDs and ultraviolet photovoltaics, as well as in thermoelectric devices such as waste heat recovery and thermoelectric generators. This paves the way for future research on rare earth-doped materials.

Citation

MohamedAmine GHEBOULI , , (2025-08-01), Magnetic, Optical and Thermoelectric Properties of EuGaN for Next-Generation Energy and Electronic Tehcnologies, Russian Journal of Physical Chemistry B, Vol:19, Issue:4, pages:783-791, Pleiades Publishing

In this research, the structural, electronic, optical, and thermoelectric properties of LiInX₂ (X = S, Te) compounds were investigated using first-principles calculations based on Density Functional Theory (DFT). The Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method implemented in the Wien2k package was employed, with the Generalized Gradient Approximation (GGA) and Tran-Blaha modified Becke-Johnson (mBJ-GGA) approximation applied to study the electronic properties. The results revealed that LiInS₂ crystallizes in an orthorhombic system with space group Pna21, while LiInTe₂ crystallizes in a tetragonal system with space group I-42d. The lattice constants and elastic parameters were calculated, showing good agreement with available experimental values. The elastic properties, including elastic constants, moduli, and mechanical stability criteria, were also evaluated to provide insight into the structural robustness and potential mechanical performance of the compounds. Electronic band structure calculations revealed that both compounds possess direct band gaps, with values of 3.61 eV for LiInS₂ and 2.33 eV for LiInTe₂ using the mBJ-GGA approximation, which are close to experimental measurements. Phonon dispersion studies were conducted to verify the dynamic stability of both compounds. Our findings demonstrate that LiInX₂ (X = S, Te) compounds possess suitable electronic band structures, strong optical absorption in the visible and UV ranges, and favorable thermoelectric characteristics. These results highlight their potential as promising materials for both optoelectronic devices and thermoelectric energy conversion technologies.

Citation

MohamedAmine GHEBOULI , , (2025-07-30), Investigation of structural elastic electronic optical and thermoelectric properties of LiInS₂ and LiInTe₂ for optoelectronic and energy conversion, Scientific Reports, Vol:15, Issue:1, pages:27859, Nature Publishing Group UK

In this study, a comprehensive analysis of the structural, electronic, and optical properties of C₁₆H₁₀X₂O₂ compounds (where X = F, Cl, Br, I) was conducted using first-principles calculations based on Density Functional Theory (DFT). The results demonstrate that the substitution of different halogens significantly influences the electronic structure and optical properties of these organic compounds. Structural data revealed a systematic relationship between crystal lattice constants and the atomic radius and electronegativity of the substituted halogen atoms, with an observed increase in the c/a and c/b ratios when moving from F to I. Electronic band structure analysis showed that the band gap follows the pattern Br < Cl < F < I, indicating that brominated derivatives exhibit more pronounced semiconducting behavior. Partial Density of States (PDOS) curves confirm the pivotal role of halogen p orbitals in determining the properties of upper valence bands. Regarding optical properties, reflectivity, absorption, refractive index, and loss function spectra were analyzed across an energy range of 0–40 eV, revealing systematic variations correlated with the type of halogen substituent. Chlorine-containing compounds exhibited the highest reflectivity, absorption, and loss function values in the 15–25 eV range, while iodine-containing compounds showed the highest refractive index in the low-energy region. These structure-property relationships provide valuable insights for designing organic materials with specific electronic and optical properties for advanced organic electronics applications.

Citation

MohamedAmine GHEBOULI , , (2025-07-17), Effect of halogen substitution on the electronic and optical behavior of C₁₆H₁₀X₂O₂ (X= F, cl, Br and I) organic semiconductors, Scientific Reports, Vol:15, Issue:1, pages:25891, Nature Publishing Group UK

In this study, a comprehensive analysis of the structural, electronic, and optical properties of C₁₆H₁₀X₂O₂ compounds (where X = F, Cl, Br, I) was conducted using first-principles calculations based on Density Functional Theory (DFT). The results demonstrate that the substitution of different halogens significantly influences the electronic structure and optical properties of these organic compounds. Structural data revealed a systematic relationship between crystal lattice constants and the atomic radius and electronegativity of the substituted halogen atoms, with an observed increase in the c/a and c/b ratios when moving from F to I. Electronic band structure analysis showed that the band gap follows the pattern Br < Cl < F < I, indicating that brominated derivatives exhibit more pronounced semiconducting behavior. Partial Density of States (PDOS) curves confirm the pivotal role of halogen p orbitals in determining the properties of upper valence bands. Regarding optical properties, reflectivity, absorption, refractive index, and loss function spectra were analyzed across an energy range of 0–40 eV, revealing systematic variations correlated with the type of halogen substituent. Chlorine-containing compounds exhibited the highest reflectivity, absorption, and loss function values in the 15–25 eV range, while iodine-containing compounds showed the highest refractive index in the low-energy region. These structure-property relationships provide valuable insights for designing organic materials with specific electronic and optical properties for advanced organic electronics applications.

Citation

AMAR Djemli , MohamedAmine GHEBOULI , M. Fatmi, B. Ghebouli, S. Alomairy, Faisal Katib Alanaz, , (2025-07-17), Effect of halogen substitution on the electronic and optical behavior of C₁₆H₁₀X₂O₂(X = F, cl, Br and I) organic semiconductors, Scientific Reports, Vol:15, Issue:1, pages:25891, Nature

This study presents a comprehensive analysis of the performance of hybrid solar cells based on copper oxide (CuO) and copper indium gallium selenide (CIGS) using the Solar Cell Capacitance Simulator-1D (SCAPS-1D) simulation software. The effects of copper oxide absorber layer thickness, acceptor density in the copper oxide and copper indium gallium selenide layers, and defect density on solar cell performance parameters, including conversion efficiency, open-circuit voltage, short-circuit current density, and fill factor, were analyzed. Results showed that the copper oxide/copper indium gallium selenide hybrid structure achieves enhanced conversion efficiency compared to the single copper oxide structure, with optimal values determined for absorber layer thickness, acceptor density, and defect density. This study provides valuable insights for developing high-efficiency, low-cost hybrid solar cells using abundant and non-toxic materials.

Citation

Idris BOUCHAMA , MohamedAmine GHEBOULI , abdelghani_rahal@univ-setif.dz, Ghebouli Brahim, Fatmi Messaoud, S. Alomairy, Boudour Samah, Benlakhdar Faiza, Chelouche Mohamed, , (2025-07-07), Optimization of structural and electronic properties in CuO/CIGS hybrid solar cells for highefficiency, sustainable energy conversion, RSC Advances, Vol:15, Issue:1, pages:23311, Royal society of chemistry

In this study, we presented a novel structure for a highly sensitive surface plasmon resonance (SPR) sensor, we propose a structure which contains six layers: BK7 prism glass, Gold thin film, Silicon sheets, Gold thin film, using transition figure of merit (FOM) 16.43 RUI−1metal dichalcogenides 2D PtSe2 layer and sample medium. We have been optimizing the thickness of each layer. The highly performance parameters in this biosensor structure are provided in terms of sensitivity(S), detection accuracy (DA), quality factor (QF) and figure of merit (FOM). Here, the addition of the hybrid Silicon—PtSe2 layer between two gold films increased the sensitivity, but we observed the (DA) and (QF) is decreased. We find the full at half maximum also decreased. We investigated the effect of gold thickness. The maximum sensitivity 200°/RIU and is gained with 35 nm Gold film, 5 nm thickness Silicon and 2 nmPtSe2 layer, we can be obtained also the configuration with 60 nm Gold thin film and 3 nm thickness Silicon (6 layer) delivers a maximum sensitivity (S) of 206°/RIU with figure of merit (FOM) of 24.03 RUI−1.Our novel structure is optimized for a highly sensitive surface plasmon resonance (SPR) sensor.

Citation

MohamedAmine GHEBOULI , , (2025-07-05), Sensitivity enhancement of biosensor (SPR) with PtSe2 using Au–Si–Au thin films, Journal of Optics, Vol:54, Issue:3, pages:1043-1051, Springer India

This study investigates the mechanical, dynamical, and thermodynamic properties of Cs2AgBiX6(X = Br, Cl) using first-principles calculations. Structural analysis confirms the cubic double perovskite arrangement, with Cs2AgBiCl6 exhibiting a more compact lattice due to the smaller ionic radius of Cl⁻ compared to Br⁻. Mechanical stability is assessed through elastic constants and Born criteria, confirming the robustness of both compounds, with Cs2AgBiCl6 demonstrating higher stiffness and resistance to deformation. Phonon dispersion calculations reveal no imaginary frequencies, verifying their dynamical stability. Thermodynamic analysis explores heat capacity, entropy, Debye temperature, and thermal expansion behavior under varying temperatures and pressures. The results indicate that Cs2AgBiCl6 possesses superior mechanical and thermal stability.

Citation

MohamedAmine GHEBOULI , , (2025-07-01), Exploring the mechanical, dynamical, and thermal stability of Cs2AgBiX6 (X = Br, Cl) for optoelectronic and thermoelectric applications, Scientific Reports, Vol:15, Issue:1, pages:20993, Nature Publishing Group UK

Adsorption is a simple and effective method to remove heavy metal ions and anionic or cationic dyes from aqueous or waste solutions. Herein, we report on the adsorption of a cationic dye crystal violet on a low-cost natural material. The diatomite was obtained from Sig deposit (west of Algeria) and then treated with 1 M HCl solution. Natural clay (diatomite) was characterized using different physical-chemical methods, including, X-ray powder diffraction, X-ray fluorescence, thermogravimetric analysis, scanning electron microscopy, and Fourier transform infrared and pH of zero charge. The effect of various experimental parameters, such as initial dye concentration, adsorbent dose, initial pH, and shaking time on adsorption was investigated. The maximum adsorption capacity was found to be 82.0 mg.g− 1 for treated Diatomite and 75.0 mg.g− 1 for raw diatomite, with equilibrium reached within 120 min. Adsorption kinetics followed the pseudo-second-order model, with high correlation coefficients (R² = 0.998 for treated diatomite and R² = 0.999 for raw diatomite). The isotherm data showed the best fit with the Langmuir model. Optimal adsorption occurred at pH 8 for treated diatomite and pH 10 for raw diatomite.

Citation

MohamedAmine GHEBOULI , , (2025-07-01), Kinetics thermodynamics and adsorption study of raw treated diatomite as a sustainable adsorbent for crystal violet dye, Scientific Reports, Vol:15, Issue:1, pages:21991, Nature Publishing Group UK

First-principles calculations carried out using the full potential linearized augmented planewave (FPLAPW) method as implemented in the Wien2K code indicate that the ground state volume of Cs2AgInBr6 and Cs2AgInCl6 is 2400 (a.u)3 and 2050 (a.u)3, which corresponds to a unit cell energy minimum of − 84,842.919545 Ryd and − 59,101.325763 Ryd. The negative formation energy, Goldschmidt tolerance factor closer to unity and octahedral factor greater than 0.41justify their thermodynamic and structural stability of our investigated double perovskites. The reported lattice constant, ground state energy, bulk modulus and its pressure derivative are closer to their available experimental and theoretical data. Optical analysis reveals high absorption in the visible to ultraviolet range, along with enhanced dielectric constants and optical conductivity. Cs2AgInX6(X = Cl, Br) double perovskites are promising candidates for solar cells, thermoelectric devices, and energy harvesting applications due to their tunable band gap, high optical absorption, and enhanced thermoelectric performance.

Citation

MohamedAmine GHEBOULI , , (2025-07-01), High performance double perovskites of Cs2InAgBr6 and Cs2InAgCl6 structural electronic optical and thermoelectric properties for next generation photovoltaics, Scientific Reports, Vol:15, Issue:1, pages:20851, Nature Publishing Group UK

Phase relations in the system Bi2O3-WO3 were studied. Six intermediate WO3, Bi2WO6, α-Bi2O3, Bi2W2O9, Bi6WO12 and Bi3W2O10.5 phases were investigated using density functional theory (DFT). The stability of phases in the ground state electronic DOS, elastic and the optical properties are reported. All elastic constants of all compounds, according to our calculations and in any type of crystalline cell, whether monoclinic, orthorhombic or tetragonal of the WO3–Bi2O3 system, are mechanically unstable. We notice that all the compounds retained its metallic character at the fermi level, except for WO3 and Bi3W2O10.5 which represent gaps. Reflectivity, absorption, conductivity, loss energy function, real and imaginary part of the dielectric function and refractive index for WO3 and α- Bi2O3 compounds are calculated with wavelength l (nm). We deduce that WO3 and α-Bi2O3 are sensitive in the ultraviolet region. The optical conductivity in the real and imaginary, confirms that WO3 is a semiconductor.

Citation

MohamedAmine GHEBOULI , , (2025-06-01), Optical, structural, electronic, and population analysis of WO3–Bi2O3 system for emerging and electrical applications, Journal of the Indian Chemical Society, Vol:102, Issue:6, pages:101729, Elsevier

This study explores the structural, elastic, mechanical, electronic, and thermodynamic properties of the LiMoN2 compound using ab initio calculations based on density functional theory (DFT). The compound’s hexagonal structure exhibits intriguing characteristics, including metallic conductivity and strong Mo–N bonding. Elastic constants confirm its stability under pressures up to 40 GPa, with an analysis of anisotropy and mechanical properties indicating a ductile nature. The electronic structure, dominated by Mo-d and N-p states, suggests potential applications in electronic systems, with features such as a high density of states at the Fermi level pointing to superconductivity. Thermodynamic properties, including heat capacities, Debye temperature, and entropy, are evaluated under varying temperatures and pressures, demonstrating its thermal stability and suitability for high-performance applications. These results provide a comprehensive understanding of the LiMoN2 compound’s properties and its potential for advanced material applications.

Citation

MohamedAmine GHEBOULI , , (2025-05-21), Structural, Elastic, Mechanic, Electronic, and Thermodynamic of LiMoN2 Compound for Electronic and Energy Storage, Physics of the Solid State, Vol:67, Issue:5, pages:356-366, Pleiades Publishing

In this study, we investigate the structural, elastic, electronic, and thermodynamic properties of LaMgX2 (X = Zn, Cd, Hg) intermetallic hydrides using first-principle calculations based on density functional theory. The compounds exhibit metallic behavior with relatively high bulk moduli, suggesting good mechanical stability. The thermodynamic parameters, such as Debye temperature and entropy, were derived and analyzed to evaluate their thermal stability. Furthermore, the hydrogen storage potential of these compounds was assessed, revealing favorable characteristics for reversible hydrogen absorption and desorption. In addition, their thermoelectric properties were investigated by evaluating key indicators such as the Seebeck coefficient, electrical conductivity, and the electronic contribution to thermal conductivity. These insights into energy transport behavior further support their multifunctional potential. Overall, these findings highlight the potential of LaMgM2 hydrides as promising candidates for hydrogen storage applications, especially in energy-efficient technologies.

Citation

MohamedAmine GHEBOULI , , (2025-05-08), Structural, elastic, electronic, thermoelectric, and thermodynamic properties of cubic LaMgX2 (X= Cd, Zn, Hg): For sustainable technologies, AIP Advances, Vol:15, Issue:5, pages:055109, AIP Publishing

The objective of this paper is to provide a comprehensive overview of optimal control models in the context of cancer treatment. We will explore how these mathematical models are used to optimize the administration of anticancer drugs. By understanding the principles behind optimal control models, we can appreciate their potential to revolutionize cancer treatment and contribute to personalized medicine. We utilize recent advancements in dynamic programming method to achieve a rigorous solution for a cancer disease model proposed by Neilan as an unsolved problem. Beginning with a certain refinement of Cauchy's method of characteristics for stratified Hamilton–Jacobi equations allows us to delineate a broad range of admissible trajectories. This, in turn, leads to the identification of a domain wherein the value function not only exists but is also generated by a certain admissible control. While the optimality is checked by using one of the well-known verification theorems taken as sufficient optimality conditions.

Citation

MohamedAmine GHEBOULI , , (2025-05-01), Optimal Control for a Mathematical Model of Cancer Disease via Dynamic Programming Approach, Optimal Control Applications and Methods, Vol:46, Issue:3, pages:1072-1080, John Wiley & Sons, Inc.

This study presents a comprehensive analysis of the performance of hybrid solar cells based on copper oxide (CuO) and copper indium gallium selenide (CIGS) using the Solar Cell Capacitance Simulator-1D (SCAPS-1D) simulation software. The effects of copper oxide absorber layer thickness, acceptor density in the copper oxide and copper indium gallium selenide layers, and defect density on solar cell performance parameters, including conversion efficiency, open-circuit voltage, short-circuit current density, and fill factor, were analyzed. Results showed that the copper oxide/copper indium gallium selenide hybrid structure achieves enhanced conversion efficiency compared to the single copper oxide structure, with optimal values determined for absorber layer thickness, acceptor density, and defect density. This study provides valuable insights for developing high-efficiency, low-cost hybrid solar cells using abundant and non-toxic materials.

Citation

MohamedAmine GHEBOULI , , (2025-04-02), Optimization of structural and electronic properties in CuO/CIGS hybrid solar cells for high-efficiency, sustainable energy conversion, RSC advances, Vol:15, Issue:29, pages:23311-23318, Royal Society of Chemistry

This work reports the determination of structural, electronic, half-metallic and magnetic properties of new double perovskites K2CuVCl6 and Rb2CuVCl6 using the full-potential linearized augmented plane wave plus local orbitals method incorporated in the WIEN2k code. The calculations performed for this prediction were framed using the density functional theory, and the exchange and correlation potential were described using the generalized gradient approximation of TB-mBJ (Tran–Blaha modified Becke–Johnson). The structural properties confirmed the stable ferromagnetic ground state of the two studied compounds. The equilibrium structural parameters, such as lattice constant (a0), bulk modulus (B0), their first pressure derivative (B′) and minimum of the total energy (E0), were determined for both the compounds. The electronic properties showed that the studied perovskite compounds were completely half-metallic materials. The half-metallic gap (EHM) values for the compounds were 1.119 eV (for K2CuVCl6) and 1.088 eV (for Rb2CuVCl6). The exchange-splitting energy (Δ(d)) was found to be large for both the compounds (Δ(d) = 3.482 eV for K2CuVCl6 and Δ(d) = 3.380 eV for Rb2CuVCl6). The calculated total magnetic moments of the two studied materials indicated major contributions from V atoms and minor contributions from Cu atoms. Owing to p–d hybridization, feeble magnetic moments were exhibited by the non-magnetic K, Rb, Cu and Cl sites, while the atomic magnetic moment of V atoms decreased from its free space charge of 3.00 μB.

Citation

MohamedAmine GHEBOULI , , (2025-03-03), Half-metallicity of novel halide double perovskites K 2 CuVCl 6 and Rb 2 CuVCl 6: application in next-generation spintronic devices, RSC advances, Vol:15, Issue:22, pages:17685-17694, Royal Society of Chemistry

Lead-based double perovskites are studied in the cubic phase using the generalized gradient approximation and the modified Becke–Johnson (mBJ-GGA) functionals as implemented in the Wien2K code. Goldschmidt tolerance factor and octahedral factor, formation enthalpy, and formation energy translate the structural, chemical, and thermodynamic stability of double perovskites studied. Phonon band structures and elastic moduli ensure the dynamic and mechanical stability of (Cs2, K2, Rb2)PbCl6. An intermediate band appears in the conduction band and the fundamental transition takes place between 3p-Cl state and 6p-Pb site. The refractive index of double perovskites (Cs2, K2, Rb2)PbCl6 in the visible and ultraviolet light hold a huge advantage for solar cell applications. The wide dielectric constant of double perovskites under study makes them capable for absorbing energy between 1 and 5 eV, and are suitable for solar power applications. (Cs2, K2, Rb2)PbCl6 have positive Seebeck coefficient, which reveals that p-type charge carriers are dominant for enhancing their performance. Cs2PbCl6 has positive thermal conductivity for both n-type and p-type character. (K2, Rb2)PbCl6 have positive thermal conductivity for n-type character. The complete analysis reveals that they are potentially significant candidates for future solar cells and energy harvesting devices.

Citation

MohamedAmine GHEBOULI , , (2025-03-02), Computational Insights into the Stability, Mechanical, Optoelectronic, and Thermoelectric Characteristics Investigation on Lead-Based Double Perovskites of (Cs2, K2, Rb2)PbCl6: Promising Candidates for Optoelectronic Applications, Advanced Theory and Simulations, Vol:8, Issue:3, pages:2400938, John Wiley & Sons, Inc.

Gabapentin (C9H17NO2) is a small organic molecule known for its pharmaceutical use, but in its solid-state crystalline forms, it exhibits promising structural and optoelectronic properties. In this work, we employed density functional theory (DFT) to investigate the structural, electronic, and optical properties of three anhydrous polymorphs (α, β, and γ) of gabapentin. The calculated band gaps for the α, β, and γ polymorphs of C9H17NO2 were found to be 4.73 eV, 4.55 eV, and 4.37 eV, respectively, based on GGA-PBE. To improve the accuracy, we also used the mBJ-GGA method, which yielded band gaps of 5.5 eV, 5.1 eV, and 5.9 eV, respectively, and these values indicated that all the three phases absorb in the ultraviolet (UV) region. Additionally, the static dielectric constants were calculated to be 2.64, 2.57, and 2.40, respectively, confirming their excellent insulating properties. These results highlight the potential of gabapentin polymorphs for UV optoelectronic applications such as UV detectors, reflective coatings, and high-frequency insulators.

Citation

MohamedAmine GHEBOULI , , (2025-03-02), Investigation of the structural, electronic and optical properties of C 9 H 17 NO 2 phases with promising potential for optoelectronic devices, RSC advances, Vol:15, Issue:40, pages:33131-33138, Royal Society of Chemistry

This study presents a comprehensive first-principles investigation of SrFAgX (X = S, Se, Te) semiconductors, focusing on the effect of chalcogen substitution on structural, elastic, electronic, and optical behavior. Using DFT-GGA calculations, we uncover systematic structure–property relationships, pressure-induced band gap tuning, and anisotropic compressibility across the series. These findings reveal how electronic and optical features can be tailored for targeted optoelectronic and spintronic applications within the generalized gradient approximation (GGA). The structural parameters, including lattice constants and internal atomic positions, show good agreement with experimental data, confirming the reliability of the computational model. The elastic constants and related mechanical moduli reveal that SrFAgS is the stiffest compound, while SrFAgSe exhibits higher flexibility, indicating tunable mechanical behavior depending on the chalcogen element. Electronic band structure analysis demonstrates that all three compounds have direct band gaps, which decrease systematically from S to Te due to enhanced orbital interactions. The calculated partial and total density of states highlight significant contributions from Ag-d and X-p states near the Fermi level, indicating strong hybridization effects. Optical properties, including dielectric function, absorption coefficient, reflectivity, refractive index, and optical conductivity, reveal systematic trends across the series, showing an enhanced optical response in SrFAgTe. These findings establish a foundation for understanding the chalcogen-dependent behavior of these materials and highlight their potential for optoelectronic, thermoelectric, and spintronic applications.

Citation

MohamedAmine GHEBOULI , , (2025-03-02), DFT-based investigation of SrFAgX (X= S, Se, Te) semiconductors: structural, electronic, elastic, and optical properties for emerging optoelectronic and spintronic applications, RSC advances, Vol:15, Issue:32, pages:26338-26346, Royal Society of Chemistry

Density functional theory calculations were performed on the stability, mechanical, optoelectronic and thermoelectric characteristics for halide double perovskites (Cs2, K2, Rb2)SnCl6. This study focuses on the effects of temperature and chemical potential on electrons transport in these materials. Key transport results include maximum Seebeck coefficient of 1500 μVK⁻1 at 300 K, maximum power factor of 2.5 1011 Ws−1K−2 at 300 K and maximum electrical conductivity (σ/τ)x1019 Wm−1K−1s−1 of 11, 6 and 9 at 300 K for (Rb2, Cs2, K2)SnCl6. High Seebeck coefficient and high electrical conductivity prove the existence of covalent bonding between Cl-3p site and (Cs-6p, K-4S, Rb-5s) states with weak van der Waals type interactions, which is also confirmed by adsorption analysis. The charge transfer is taking place via Cl-3p and (Cs-6p, K-4S, Rb-5s) states between upper valence band and lower conduction band. The estimated power factor offers useful guidelines for tuning and improving the thermoelectric performance. The density of states predicts the n-type conductivity in all compounds which was confirmed from positive value of Seebeck coefficient.

Citation

MohamedAmine GHEBOULI , , (2025-03-01), Stability, mechanical, optoelectronic and thermoelectric behaviors of inorganic metal halide double perovskites (Cs2, K2, Rb2) SnCl6: Promising green energy alternatives, Solid State Communications, Vol:397, Issue:, pages:115831, Pergamon

Mn-doped ZnO thin films with varying Mn concentrations were synthesized on glass substrates using the pneumatic spray technique. Energy-dispersive X-ray (EDX) analysis confirmed the substitution of Zn by Mn in the ZnO matrix. X-ray photoelectron spectroscopy (XPS) revealed characteristic spin-orbit energy states of Zn:2p and Mn:3d, indicating strong Mn-ZnO interactions. Microstructural analysis showed non-uniform extended lines and spherical grains, with decreasing grain size as Mn concentration increased. X-ray diffraction (XRD) confirmed a polycrystalline hexagonal structure, with experimentally determined lattice parameters a = 3.1453 Å, c = 5.1353 Å, in agreement with CASTEP calculations. Optical measurements indicated ~ 80% absorbance in the visible range, with a shift from blue to red as Mn content increased, suggesting bandgap modulation. These findings highlight the potential of Mn-doped ZnO films for tunable optoelectronic applications.

Citation

MohamedAmine GHEBOULI , , (2025-02-27), Experimental investigation of structural and optical properties of Mn-doped ZnO thin films deposited by pneumatic spray technique, Scientific Reports, Vol:15, Issue:1, pages:7086, Nature Publishing Group UK

The CsCl-structured MgCa intermetallic compound was examined through computational quantum mechanics, employing DFT methodology via CASTEP implementation. Analysis of volumetric energy correlations revealed fundamental parameters: a 3.868 Å lattice dimension, 27.99 GPa compressibility factor, and corresponding pressure coefficient of 3.70. The LDA framework produced crystallographic and mechanical flexibility values consistent with previously published computational findings. Thermophysical behavior was quantified using Debye quasi-harmonic approximations spanning thermal conditions (0–800 K) and compression states (0–10 GPa). Under standard reference conditions (P = 0 GPa, T = 0 K), the characteristic vibrational temperature parameter reached 319.23 K, exhibiting remarkable concordance with the independently calculated elastic-based estimate of 321.1 K.

Citation

MohamedAmine GHEBOULI , , (2025-02-09), Structural elastic and thermodynamic properties of cubic CsCl type MgCa using ab initio approach, Scientific Reports, Vol:15, Issue:1, pages:18781, Nature Publishing Group UK

The Pseudopotential method coupled with plane waves implemented in the quantum espresso code was used in the prediction of the structural parameters and elastic constants of SrCuX (X = P, Sb) materials. The obtained results of lattice parameters and bulk modulus at equilibrium agree well with their experimental and theoretical data cited in the literature. The calculated Young’s modulus of SrCuX (X = P, Sb) aggregate thermoelectric materials are 109.25 GPa and 78.22 GPa, while their Debye temperatures are 364.2 K and 261.8 K. The vibration energy of phonons is 24.14 kJ/mol and 23.37 kJ/mol for SrCuP and SrCuSb. Our thermodynamic parameters increase monotonically with temperatures for both SrCuP and SrCuSb materials. To the best of our knowledge, there are no data available in the literature on the elastic and thermodynamic parameters of SrCuX (X = P, Sb) compounds, then our results are prediction. The absence of virtual phonon frequencies indicates high dynamic stability in both materials, with a band gap about 1 THz between optical and acoustic phonons in SrCuP and SrCuSb.

Citation

MohamedAmine GHEBOULI , , (2025-02-03), Predicted thermodynamic structural and elastic properties of SrCuP and SrCuSb for thermoelectric applications, Scientific Reports, Vol:15, Issue:1, pages:4082, Nature Publishing Group UK

The Pseudopotential method coupled with plane waves implemented in the quantum espresso code was used in the prediction of the structural parameters and elastic constants of SrCuX (X = P, Sb) materials. The obtained results of lattice parameters and bulk modulus at equilibrium agree well with their experimental and theoretical data cited in the literature. The calculated Young’s modulus of SrCuX (X = P, Sb) aggregate thermoelectric materials are 109.25 GPa and 78.22 GPa, while their Debye temperatures are 364.2 K and 261.8 K. The vibration energy of phonons is 24.14 kJ/mol and 23.37 kJ/ mol for SrCuP and SrCuSb. Our thermodynamic parameters increase monotonically with temperatures for both SrCuP and SrCuSb materials. To the best of our knowledge, there are no data available in the literature on the elastic and thermodynamic parameters of SrCuX (X = P, Sb) compounds, then our results are prediction. The absence of virtual phonon frequencies indicates high dynamic stability in both materials, with a band gap about 1 THz between optical and acoustic phonons in SrCuP and SrCuSb

Citation

MohamedAmine GHEBOULI , , (2025-01-28), Predicted thermodynamic structural and elastic properties of SrCuP and SrCuSb for thermoelectric applications, Scientific Reports, Vol:25, Issue:, pages:88280, nature

Mn-doped ZnO thin films with varying Mn concentrations were synthesized on glass substrates using the pneumatic spray technique. Energy-dispersive X-ray (EDX) analysis confirmed the substitution of Zn by Mn in the ZnO matrix. X-ray photoelectron spectroscopy (XPS) revealed characteristic spin-orbit energy states of Zn:2p and Mn:3d, indicating strong Mn-ZnO interactions. Microstructural analysis showed non-uniform extended lines and spherical grains, with decreasing grain size as Mn concentration increased. X-ray diffraction (XRD) confirmed a polycrystalline hexagonal structure, with experimentally determined lattice parameters a = 3.1453 Å, c = 5.1353 Å, in agreement with CASTEP calculations. Optical measurements indicated ~ 80% absorbance in the visible range, with a shift from blue to red as Mn content increased, suggesting bandgap modulation. These findings highlight the potential of Mn-doped ZnO films for tunable optoelectronic applications.

Citation

Idris BOUCHAMA , MohamedAmine GHEBOULI , abdelghani_rahal@univ-setif.dz, Faisal Katib Alanazi, Ghebouli Brahim, Fatmi Messaoud, Chihi Tayeb, Talal Mohamed Althagafi, Khattab Khatir, , (2025-01-27), Experimental investigation of structural and optical properties of Mn-doped ZnO thin films deposited by pneumatic spray technique, Scientific Reports, Vol:1, Issue:15, pages:7086, Nature Portfolio

This prediction evaluates the different physical characteristics of magnetic materials X3FeO4 (X = Mg, Ca and Sr) by using density functional theory (DFT). The generalized gradient approximation (GGA) approach is chosen to define the exchange and correlation potential. The structural study of the compounds X3FeO4 (X = Mg, Ca and Sr) shows that the ferromagnetic phase is the more stable ground state, where all the parameters of the network are given at equilibrium. The calculated elastic constants confirm their stability in the cubic structure. The electronic characteristics calculated using the GGA and GGA + U approaches prove that all these compounds are semi-metallic with a wide band gap (EHM) and a high Curie temperature (TC). Furthermore, the magnetic moments of the studied compounds are calculated in order to claim their half-metallicity behavior. The p-d hybridization between the 3d-Fe and 2p-O states generates weak magnetic moments in the non-magnetic X and O sites, and decreases the Fe atomic moment relative to its free space charge of 4 µB. The thermal parameters including the thermal expansion coefficient, the heat capacity at constant volume and the Debye temperature were calculated for these compounds.

Citation

MohamedAmine GHEBOULI , karim BOUFERRACHE , Mohammed El Amine Monir, Abdelkarim Bendoukha Reguig, , (2025-01-23), Structural, elastic, electronic, magnetic and thermal properties of X3FeO4 (X = mg, ca and Sr) materials, Scientific Reports, Vol:15, Issue:1, pages:2957, Nature Publishing Group UK

This prediction evaluates the different physical characteristics of magnetic materials X3FeO4 (X = Mg, Ca and Sr) by using density functional theory (DFT). The generalized gradient approximation (GGA) approach is chosen to define the exchange and correlation potential. The structural study of the compounds X3FeO4 (X = Mg, Ca and Sr) shows that the ferromagnetic phase is the more stable ground state, where all the parameters of the network are given at equilibrium. The calculated elastic constants confirm their stability in the cubic structure. The electronic characteristics calculated using the GGA and GGA + U approaches prove that all these compounds are semi-metallic with a wide band gap (EHM) and a high Curie temperature (TC). Furthermore, the magnetic moments of the studied compounds are calculated in order to claim their half-metallicity behavior. The p-d hybridization between the 3d-Fe and 2p-O states generates weak magnetic moments in the non-magnetic X and O sites, and decreases the Fe atomic moment relative to its free space charge of 4 µB. The thermal parameters including the thermal expansion coefficient, the heat capacity at constant volume and the Debye temperature were calculated for these compounds.

Citation

MohamedAmine GHEBOULI , , (2025-01-23), Structural, elastic, electronic, magnetic and thermal properties of X3FeO4 (X = mg, ca and Sr) materials, Scientific Reports, Vol:15, Issue:1, pages:2957, Nature Publishing Group UK

Density functional theory calculations were performed on the stability, mechanical, optoelectronic and thermoelectric characteristics for halide double perovskites (Cs2, K2, Rb2)SnCl6. This study focuses on the effects of temperature and chemical potential on electrons transport in these materials. Key transport results include maximum Seebeck coefficient of 1500 μVK⁻1 at 300 K, maximum power factor of 2.5 1011 Ws−1K−2 at 300 K and maximum electrical conductivity (σ/τ)x1019 Wm−1K−1s−1 of 11, 6 and 9 at 300 K for (Rb2, Cs2, K2)SnCl6. High Seebeck coefficient and high electrical conductivity prove the existence of covalent bonding between Cl-3p site and (Cs-6p, K-4S, Rb-5s) states with weak van der Waals type interactions, which is also confirmed by adsorption analysis. The charge transfer is taking place via Cl-3p and (Cs-6p, K-4S, Rb-5s) states between upper valence band and lower conduction band. The estimated power factor offers useful guidelines for tuning and improving the thermoelectric performance. The density of states predicts the n-type conductivity in all compounds which was confirmed from positive value of Seebeck coefficient.

Citation

MohamedAmine GHEBOULI , karim BOUFERRACHE , , (2025-01-12), Stability, mechanical, optoelectronic and thermoelectric behaviors of inorganic metal halide double perovskites (Cs2, K2, Rb2)SnCl6: Promising green energy alternatives, Solid State Communications, Vol:397, Issue:10, pages:115831, PERGAMON-ELSEVIER SCIENCE LTD

Density functional theory calculations were performed on the stability, mechanical, optoelectronic and ther- moelectric characteristics for halide double perovskites (Cs2, K2, Rb2)SnCl6. This study focuses on the effects of temperature and chemical potential on electrons transport in these materials. Key transport results include maximum Seebeck coefficient of 1500 μVK⁻1 at 300 K, maximum power factor of 2.5 1011 Ws 1K 2 at 300 K and maximum electrical conductivity (σ/τ)x1019 Wm 1K 1s 1 of 11, 6 and 9 at 300 K for (Rb2, Cs2, K2)SnCl6. High Seebeck coefficient and high electrical conductivity prove the existence of covalent bonding between Cl-3p site and (Cs-6p, K-4S, Rb-5s) states with weak van der Waals type interactions, which is also confirmed by adsorption analysis. The charge transfer is taking place via Cl-3p and (Cs-6p, K-4S, Rb-5s) states between upper valence band and lower conduction band. The estimated power factor offers useful guidelines for tuning and improving the thermoelectric performance. The density of states predicts the n-type conductivity in all compounds which was confirmed from positive value of Seebeck coefficient.

Citation

MohamedAmine GHEBOULI , , (2025-01-07), Stability, mechanical, optoelectronic and thermoelectric behaviors of inorganic metal halide double perovskites (Cs2, K2, Rb2) SnCl6: Promising Green Energy Alternatives, Solid State Communications, Vol:397, Issue:, pages:115831, ScienceDirect

This study examines the structural, electronic, and thermoelectric properties of trigonal-phase copper germanium phosphide (CuGe 2P 3) using density functional theory (DFT) calculations. The bulk modulus is 68.98 GPa with a pressure derivative of 4.53, obtained from the Birch–Murnaghan equation of state based on energy–volume data. This is lower than the 86.7 GPa reported for the disordered zincblende phase, indicating significant structural differences. Thermoelectric transport properties were evaluated at 100, 300, and 500 K. At 100 K, strong p-type transport with high Seebeck coefficients was observed, highlighting pronounced low- temperature electronic sensitivity. Using a representative lattice thermal conductivity, the estimated figure of merit zT reaches ∼0.29 at 500 K, suggesting moderate thermoelectric performance. These results demonstrate that CuGe2P 3 combines favorable structural stability with promising transport behavior, making it a potential candidate for mid-temperature thermoelectric applications

Citation

MohamedAmine GHEBOULI , , (2025-01-02), Structural electronic and thermoelectric properties of CuGe2P3 ternary compound in trigonal phase promising for electronic applications, The European Physical Journal Applied Physics, Vol:100, Issue:, pages:29, EDP Sciences

This work investigates the mechanical properties of B2-type CoTi material, using the density functional theory within the pseudopotential method and a plane waves basis set as implemented in the Quantum Espresso code. Our calculation yielded values of Debye temperature θD = 414.6 K and elastic constants C11 = 226.50 GPa, C12 = 129.55 GPa, and C44 = 226.50 GPa, respectively. To test the incertitude of calculated elastic constants Cij for B2-type CoTi intermetallic compound, we compared our obtained results with the experimental values of the literature. Our findings show a good agreement with experimental data. Furthermore, using an approximation based on the quasi-harmonic model, we explore various thermodynamic properties of the B2-type CoTi intermetallic compound. The thermodynamic properties obtained in this study reveal that the free energy decreases gradually with the augmentation of the temperature, while both the heat capacity as well as the entropy increase with the raising of the temperature. At T = 298 K, our calculation yielded values of entropy S = 68.35 J mol–1 K–1 and heat capacity CV = 46.61 J mol–1 K–1, respectively. To the authors’ knowledge, no previous study has reported theoretical data on the thermodynamic properties for CoTi material.

Citation

MohamedAmine GHEBOULI , , (2025-01-01), Computational investigation of thermodynamic and mechanical properties of B2-type CoTi intermetallic compound, Physics of the Solid State, Vol:67, Issue:1, pages:68-74, Pleiades Publishing

The objective of this paper is to provide a comprehensive overview of optimal control models in the context of cancer treatment. We will explore how these mathematical models are used to optimize the administration of anticancer drugs. By understanding the principles behind optimal control models, we can appreciate their potential to revolutionize cancer treatment and contribute to personalized medicine. We utilize recent advancements in dynamic programming method to achieve a rigorous solution for a cancer disease model proposed by Neilan as an unsolved problem. Beginning with a certain refinement of Cauchy's method of characteristics for stratified Hamilton–Jacobi equations allows us to delineate a broad range of admissible trajectories. This, in turn, leads to the identification of a domain wherein the value function not only exists but is also generated by a certain admissible control. While the optimality is checked by using one of the well-known verification theorems taken as sufficient optimality conditions.

Citation

MohamedAmine GHEBOULI , , (2024-12-23), Optimal Control for a Mathematical Model of Cancer Disease via Dynamic Programming Approach, Optimal Control Applications and Methods, Vol:175, Issue:, pages:123, John Wiley & Sons, Inc.

Lead-based double perovskites are studied in the cubic phase using the generalized gradient approximation and the modified Becke–Johnson (mBJ-GGA) functionals as implemented in the Wien2K code. Goldschmidt tolerance factor and octahedral factor, formation enthalpy, and formation energy translate the structural, chemical, and thermodynamic stability of double perovskites studied. Phonon band structures and elastic moduli ensure the dynamic and mechanical stability of (Cs2, K2, Rb2)PbCl6. An intermediate band appears in the conduction band and the fundamental transition takes place between 3p-Cl state and 6p-Pb site. The refractive index of double perovskites (Cs2, K2, Rb2)PbCl6 in the visible and ultraviolet light hold a huge advantage for solar cell applications. The wide dielectric constant of double perovskites under study makes them capable for absorbing energy between 1 and 5 eV, and are suitable for solar power applications. (Cs2, K2, Rb2)PbCl6 have positive Seebeck coefficient, which reveals that p-type charge carriers are dominant for enhancing their performance. Cs2PbCl6 has positive thermal conductivity for both n-type and p-type character. (K2, Rb2)PbCl6 have positive thermal conductivity for n-type character. The complete analysis reveals that they are potentially significant candidates for future solar cells and energy harvesting devices.

Citation

MohamedAmine GHEBOULI , karim BOUFERRACHE , , (2024-12-16), Computational Insights into the Stability, Mechanical, Optoelectronic, and Thermoelectric Characteristics Investigation on Lead-Based Double Perovskites of (Cs2, K2, Rb2)PbCl6: Promising Candidates for Optoelectronic Applications, Advanced Theory and Simulations, Vol:10, Issue:2, pages:2400938, WILEY-V C H VERLAG GMBH

First-principle calculations using the Wien2k code and the GGA-mBJ exchange potential were used in the study of the thermodynamic, dynamic, chemical and elastic stability, as well as the electronic, optical and thermoelectric properties of Cs2(Sn, Pt, Te)I6. The presence of an intermediate band in Cs2(Sn, Pt, Te)I6 semiconductors confirmed by absorption peaks appeared at photon energy corresponding to the band gap enhances the efficiency of solar cells. The ideal band gap, high dielectric constants and optimal absorption make the double perovskites under study perform well in solar cells. The calculated minimum formation energy, Helmholtz free energy and phonon modes through the first Brillouin zone for the investigated Cs2(Sn, Pt, Te)I6 family confirm their thermal, thermodynamic and dynamic stability. The acoustic phonon contribution modes come from the Cs-6s and I-5p electrons, while the Pt-6s, Sn-5p, Te-5p and I-5p electrons participate in the optical phonon modes. The narrowness of the upper valence band and the band gap in the visible region for advantage this double perovskite in energy harvesting. The geometric Goldschmidt tolerance factor value between 0.8 and 1.0 and octahedral factor 0.41 indicate that double perovskite is more stable.

Citation

MohamedAmine GHEBOULI , ,(2024-11-30), Thermal, optoelectronic of Organic-inorganic hexahalometalate single double perovskites semiconductors for solar energy applications,1ST International Conference On Technological Application Of Materials (ICTAM24),University Setif

This work investigates the mechanical properties of B2-type CoTi material, using the density func- tional theory within the pseudopotential method and a plane waves basis set as implemented in the Quantum Espresso code. Our calculation yielded values of Debye temperature θD = 414.6 K and elastic constants C11 = 226.50 GPa, C12 = 129.55 GPa, and C44 = 226.50 GPa, respectively. To test the incertitude of calculated elastic constants Cij for B2-type CoTi intermetallic compound, we compared our obtained results with the experimental values of the literature. Our findings show a good agreement with experimental data. Further- more, using an approximation based on the quasi-harmonic model, we explore various thermodynamic properties of the B2-type CoTi intermetallic compound. The thermodynamic properties obtained in this study reveal that the free energy decreases gradually with the augmentation of the temperature, while both the heat capacity as well as the entropy increase with the raising of the temperature. At T = 298 K, our calculation yielded values of entropy S = 68.35 J mol –1 K –1 and heat capacity CV = 46.61 J mol –1 K –1 , respectively. To the authors’ knowledge, no previous study has reported theoretical data on the thermodynamic properties for CoTi material

Citation

MohamedAmine GHEBOULI , , (2024-11-27), Computational Investigation of Thermodynamic and Mechanical Properties of B2-type CoTi Intermetallic Compound, hysics of the Solid State, Vol:67, Issue:1, pages:68-74, Pleiades Publishing

This paper studies a novel surface plasmon resonance (SPR) biosensor using a BK7 glass prism, a copper (Cu) metal plasmonic layer, which combine a halide perovskite (FASnI3) with two-dimensional (2D) materials such as phosphorus black, graphene and TMDC (MoS2, MoSe2, WS2, WSe2) for the detection of breast cancer cells. We have optimized the thickness of each layer in order to obtain maximum sensitivity. A numerical study mainly uses the transfer matrix principle, while the attenuation total reflection method involves examining the reflection properties. The evaluation of SPR biosensor configurations serves to obtain optimal performance. The simulation results indicate that the integration of halide perovskite (FASnI3) and 2D materials into the BK7/Cu/medium sensing structure significantly improves the sensitivity and figure of merit (ZT). The outstanding results in terms of sensor performance characteristics are observed in the BK7/Cu (48 nm)/FASnI3 (5 nm)/BP (0.53 nm) configuration. The figure of merit and sensitivity estimated at 123.11 RIU− 1 and 459.28◦/RIU, with a notable improvement of 338.45 %.

Citation

MohamedAmine GHEBOULI , , (2024-11-01), Ultra-sensitivity of surface plasmon resonance sensor using halide perovskite FASnI3 and 2D materials on Cu thin films, Results in Physics, Vol:66, Issue:, pages:108004, ScienceDirect

Hybrid organic, halide, and divalent metal double perovskites were computed in the cubic structure using GGA and mBJ-GGA functionals. Goldschmidt tolerance factor and octahedral factor, Helmholtz free energy and formation energy translate the structural, chemical and thermodynamic stability of compounds studied. The equilibrium lattice constant for and deviates from the experimental value by 4.3% and 3.1%. Elastic constants are significantly smaller due to their larger reticular distances and lower Coulomb forces and hardness. The high dynamic lattice anharmonicity reduces their electronic conductivity, which gives them a usage advantage in the thermoelectric field. predict the indirect band gap X-L nature, while that of is direct Γ-Γ. The band gap in the visible region provides an advantage for the energy harvesting property. The electronic transition in double perovskites under study takes place between Br-4p and K-4s orbitals. Hybrid organic-inorganic halide perovskites are excellent semiconductors

Citation

karim BOUFERRACHE , MohamedAmine GHEBOULI , ,(2024-10-30), Thermal, optoelectronic of Organic-inorganic hexahalometalate hybrid single double perovskites semiconductors for solar energy applications,AT THE 1ST INTERNATIONAL CONFERENCE ON TECHNOLOGICAL APPLICATION OF MATERIALS (ICTAM'24),Sétif, Algeria

First-principle calculations using the Wien2k code and the GGA-mBJ exchange potential were used in the study of the thermodynamic, dynamic, chemical and elastic stability, as well as the electronic, optical and thermoelectric properties of Cs2(Sn, Pt, Te)I6. The presence of an intermediate band in Cs2(Sn, Pt, Te)I6 semiconductors confirmed by absorption peaks appeared at photon energy corresponding to the band gap enhances the efficiency of solar cells. The ideal band gap, high dielectric constants and optimal absorption make the double perovskites under study perform well in solar cells. The calculated minimum formation energy, Helmholtz free energy and phonon modes through the first Brillouin zone for the investigated Cs2(Sn, Pt, Te)I6 family confirm their thermal, thermodynamic and dynamic stability. The acoustic phonon contribution modes come from the Cs-6s and I-5p electrons, while the Pt-6s, Sn-5p, Te-5p and I-5p electrons participate in the optical phonon modes. The narrowness of the upper valence band and the band gap in the visible region for Cs2PtI6 advantage this double perovskite in energy harvesting. The geometric Goldschmidt tolerance factor value between 0.8 and 1.0 and octahedral factor 0.41 indicate that Cs2SnI6 double perovskite is more stable.

Citation

MohamedAmine GHEBOULI , , (2024-10-01), Thermal, optoelectronic and thermoelectric properties of inorganic double perovskites semiconductors Cs2(Sn, Pt, Te)I6 for application as intermediate-band solar cells, Solid State Communications, Vol:389, Issue:, pages:115522, ScienceDirect

We analyse a detailed investigation of structure, electronic, optical, magnetic and thermoelectric properties of (Cs, Rb, K)2MnF6 double perovskites with cubic Fm3m space group. The calculation method was the augmented plane-wave functions plus local orbitals as implemented in the WIEN2k code and the GGA followed by the most accurate GGA-mBJ as exchange potentials. The precision of our K2MnF6, Rb2MnF6 and Cs2MnF6 lattice constant compared with their available experimental data is in the range 1.2 % to 3.6 %. The calculated band gap of K2MnF6, Rb2MnF6 and Cs2MnF6 materials advantages them for use in light-emitting diode technology. These materials exhibit ferromagnetic behavior. The negative formation energy, free Helmholtz energy and the dispersion of phonons confirm their thermal, thermodynamic and dynamic stability. The calculated band gap of K2MnF6, Rb2MnF6 and Cs2MnF6 materials advantages them for use in light-emitting diode technology. The p-type charge carriers, direct band gap, and flat conduction and valence bands make them as good thermoelectric materials. The major contribution to the magnetization comes from the unfilled Mn-3d orbital. The high static dielectric constant reduces the recombination rate of charge carriers and the presence of absorption peaks in the ultraviolet region are advantageous in the exploitation in the optoelectronic field. The flat valence and conduction bands, high p-type conductivity, good thermoelectric parameters, as well as non-toxicity make these compounds mainly attractive in the thermoelectric application.

Citation

MohamedAmine GHEBOULI , , (2024-10-01), Study of structural, elastic, electronic, optical, magnetic and thermoelectric characteristics of Hexafluoromanganets A2MnF6 (A = Cs, Rb, K) cubic double perovskites, Materials Science & Engineering B, Vol:308, Issue:, pages:117550, ScienceDirect

The molecular structures of WCl6, WCl5, WCl4, WCl3 have been optimized by density functional theory calculations. We report the stability of the phases in the ground state, the total energies and the optoelectronic properties of the W-Cl system. We find that the material having a low tungsten concentration shows a low DOS at the Fermi level, which implies a high resistivity. Both polymorphs of WCl6 are crystalline solids at room temperature and show the (α- WCl6) and (β- WCl6) phases of space group R-3 and P-3 m1 observed at 228 ◦C. The change in temperature influences the structural, electronic and optical properties. The object of this paper does not concern only the study of all phases, but also one controls the physical states of the molecular materials when they are subjected to polymorphic changes. Calculations on the molecular structure under symmetry indicated an orbitally degenerate ground state with bond distances in good agreement with experiment.

Citation

MohamedAmine GHEBOULI , , (2024-09-01), Prediction study of Optical, structural and electronic properties of WClx (x = 3 to 6), Computational and Theoretical Chemistry, Vol:1239, Issue:, pages:114792, ScienceDirect

We analyse a detailed investigation of structure, electronic, optical, magnetic and thermoelectric properties of (Cs, Rb, K)2MnF6 double perovskites with cubic space group. The calculation method was the augmented plane-wave functions plus local orbitals as implemented in the WIEN2k code and the GGA followed by the most accurate GGA-mBJ as exchange potentials. The precision of our K2MnF6, Rb2MnF6 and Cs2MnF6 lattice constant compared with their available experimental data is in the range 1.2 % to 3.6 %. The calculated band gap of K2MnF6, Rb2MnF6 and Cs2MnF6 materials advantages them for use in light-emitting diode technology. These materials exhibit ferromagnetic behavior. The negative formation energy, free Helmholtz energy and the dispersion of phonons confirm their thermal, thermodynamic and dynamic stability. The calculated band gap of K2MnF6, Rb2MnF6 and Cs2MnF6 materials advantages them for use in light-emitting diode technology. The p-type charge carriers, direct band gap, and flat conduction and valence bands make them as good thermoelectric materials. The major contribution to the magnetization comes from the unfilled Mn-3d orbital. The high static dielectric constant reduces the recombination rate of charge carriers and the presence of absorption peaks in the ultraviolet region are advantageous in the exploitation in the optoelectronic field. The flat valence and conduction bands, high p-type conductivity, good thermoelectric parameters, as well as non-toxicity make these compounds mainly attractive in the thermoelectric application.

Citation

karim BOUFERRACHE , MohamedAmine GHEBOULI , , (2024-07-14), Study of structural, elastic, electronic, optical, magnetic and thermoelectric characteristics of Hexafluoromanganets A2MnF6 (A= Cs, Rb, K) cubic double perovskites, Materials Science and Engineering: B, Vol:308, Issue:10, pages:117550, Elsevier

First-principle calculations using the Wien2k code and the GGA-mBJ exchange potential were used in the study of the thermodynamic, dynamic, chemical and elastic stability, as well as the electronic, optical and thermoelectric properties of Cs2(Sn, Pt, Te)I6. The presence of an intermediate band in Cs2(Sn, Pt, Te)I6 semiconductors confirmed by absorption peaks appeared at photon energy corresponding to the band gap enhances the efficiency of solar cells. The ideal band gap, high dielectric constants and optimal absorption make the double perovskites under study perform well in solar cells. The calculated minimum formation energy, Helmholtz free energy and phonon modes through the first Brillouin zone for the investigated Cs2(Sn, Pt, Te)I6 family confirm their thermal, thermodynamic and dynamic stability. The acoustic phonon contribution modes come from the Cs-6s and I-5p electrons, while the Pt-6s, Sn-5p, Te-5p and I-5p electrons participate in the optical phonon modes. The narrowness of the upper valence band and the band gap in the visible region for advantage this double perovskite in energy harvesting. The geometric Goldschmidt tolerance factor value between 0.8 and 1.0 and octahedral factor 0.41 indicate that double perovskite is more stable.

Citation

karim BOUFERRACHE , MohamedAmine GHEBOULI , , (2024-06-02), Thermal, optoelectronic and thermoelectric properties of inorganic double perovskites semiconductors Cs2 (Sn, Pt, Te) I6 for application as intermediate-band solar cells, Solid State Communications, Vol:389, Issue:10, pages:115522, Pergamon

Effect of functional on structural, elastic, optoelectronic and thermoelectric characteristics of semiconducting MgX2Se4 (X = Lu, Y) spinels has been realized by WIEN2k code. The lattice constant of MgY2Se4 is slightly greater than that of MgLu2Se4, and these quantities are slightly deviated from the experimental values, where the error does not exceed 1.3%. The cohesive energy proves that both spinels are chemically stable in the normal case, and this stability is more pronounced in MgLu2Y4. The large ionic radius of Lu compared to Y explains the high bulk modulus of MgY2Se4 as well as its hardness. The spinels under study have U ? U direct band gap located between 1.178 and 1.4 eV for all the functionals, proving their semiconductor nature. Se-s, Y-d, Lu-d states in MgY2Se4 and MgLu2Se4 dominate the upper valence band, while the first conduction band located between Fermi level and 1.5 eV is empty. There is a strong coupling between Se-p–Lu-p sites for MgLu2Se4 and Se-p–Y-p states in MgY2Se4, which reflects their hybridization. The high absorption in the ultraviolet range, the band gap between 1 and 2.4 eV and the refractive index in the range of 2.29–2.61 favour these spinels as absorbers in solar cells. Peaks of all the optical quantities studied relating to the mBJ–GGA functional are shifted to the right compared with GGA and GGA?SO approximations. The thermoelectric parameters were investigated as a function of photon energy and temperature using GGA?SO functional.

Citation

MohamedAmine GHEBOULI , , (2024-06-01), Effect of functional on structural, elastic stability, optoelectronic and thermoelectric characteristics of semiconducting MgX2Se4 (X 5 Lu, Y) spinels, Bulletin of Materials Science, Vol:47, Issue:2, pages:1-14, Indian Academy of Sciences

This study investigated the synthesis and analysis of Co–Zn nanoferrites, specifically Co0.6Zn0.4Fe2O4, using the sol–gel method. The morphological, structural, and electrical properties of these ferrites were explored. The Co0.6Zn0.4Fe2O4 spinel ferrite was synthesized using metal nitrate reagents and ethylene glycol, followed by a series of heating and sintering processes. Rietveld-refined X-ray diffraction (XRD) confirmed the crystalline structure and phase purity, revealing a monophasic spinel structure. Scanning electron microscopy (SEM) analysis showed distinct grain agglomeration and porosity, indicating the material’s unique microstructure. Impedance measurements further characterized the optical and electrical properties. The electrical conductivity of Co0.6Zn0.4Fe2O4 demonstrated a thermally activated conduction process, adhering to Jonscher’s universal power law. The complex impedance analysis revealed thermally activated behavior, confirming the presence of relaxation processes influenced by temperature. Nyquist plots indicated the contributions of grains, grain boundaries, and electrodes to the electrical behavior. The complex electrical modulus and dielectric studies provided insights into the dielectric characteristics, confirming high space charge polarization at grain boundaries and low dielectric loss. These findings suggested that Co0.6Zn0.4Fe2O4 nanoferrites synthesized via the sol–gel method exhibited desirable electrical and structural properties, making them promising for various technological applications.

Citation

MohamedAmine GHEBOULI , , (2024-05-20), Dielectric and structural properties of Co0.6Zn0.4Fe2O4 nanoferrites: sol–gel synthesis, Journal of Sol-Gel Science and Technology, Vol:20, Issue:, pages:1-18, Springer US

Effect of functional on structural, elastic, optoelectronic and thermoelectric characteristics of semiconducting MgX2Se4 (X = Lu, Y) spinels has been realized by WIEN2k code. The lattice constant of MgY2Se4 is slightly greater than that of MgLu2Se4, and these quantities are slightly deviated from the experimental values, where the error does not exceed 1.3%. The cohesive energy proves that both spinels are chemically stable in the normal case, and this stability is more pronounced in MgLu2Y4. The large ionic radius of Lu compared to Y explains the high bulk modulus of MgY2Se4 as well as its hardness. The spinels under study have Г → Г direct band gap located between 1.178 and 1.4 eV for all the functionals, proving their semiconductor nature. Se-s, Y-d, Lu-d states in MgY2Se4 and MgLu2Se4 dominate the upper valence band, while the first conduction band located between Fermi level and 1.5 eV is empty. There is a strong coupling between Se-p–Lu-p sites for MgLu2Se4 and Se-p–Y-p states in MgY2Se4, which reflects their hybridization. The high absorption in the ultraviolet range, the band gap between 1 and 2.4 eV and the refractive index in the range of 2.29–2.61 favour these spinels as absorbers in solar cells. Peaks of all the optical quantities studied relating to the mBJ–GGA functional are shifted to the right compared with GGA and GGA+SO approximations. The thermoelectric parameters were investigated as a function of photon energy and temperature using GGA+SO functional.

Citation

karim BOUFERRACHE , MohamedAmine GHEBOULI , , (2024-05-18), Effect of functional on structural, elastic stability, optoelectronic and thermoelectric characteristics of semiconducting MgX2Se4 (X= Lu, Y) spinels, Bulletin of Materials Science, Vol:47, Issue:2, pages:14, Indian Academy of Sciences

In this comprehensive study, we synthesized Co0.6Zn0.4Fe2O4 cubic spinel via the sol–gel method and characterized its structural, thermal, and optical properties. X-ray diffraction (XRD) verified the crystallization within the cubic Fd-3 m space group, and a detailed analysis determined a crystallite size ranging from 47 to 58 nm. Notably, the calculated crystallite size of 49.4 nm revealed inherent limitations in Scherer’s formula, which does not account for intrinsic strain effects from crystal defects, grain boundaries, and stacking. Optical investigations, utilizing UV–Vis absorption spectroscopy, unveiled a direct optical band gap of 1.26 eV, suggesting semiconductor behavior. The material’s thermal conductivity was found to be highly temperature sensitive, reaching its maximum value for both spin orientations at 900 K, with a quantified value of ke/τ = 4 × 1014 W/(mKs). This thermal behavior, along with the observed disorder (Eu value of 1.41 eV) and higher Urbach energy, offers valuable insights into the material’s response under varying temperature conditions, essential for applications in diverse technological domains.

Citation

MohamedAmine GHEBOULI , , (2024-05-15), Prediction study of structural, thermal, and optical characterization of Co 0.6Zn0.4Fe2O4 cubic spinel synthesized via sol–gel method for energy storage, Journal of the Korean Physical Society, Vol:11, Issue:, pages:1-11, The Korean Physical Society

Hybrid organic-inorganic double perovskites have garnered significant attention as promising materials for solar energy applications due to their tunable optoelectronic properties, structural versatility, and potential for low-cost fabrication. In this work, we explore the structural, electronic, and optical properties of K2(Sn,Pt,Te)Br6 hexahalometallate single crystals using a combination of experimental synthesis and first-principles density functional theory (DFT) calculations. The synthesized single crystals exhibit a cubic double perovskite structure with high crystallinity and stability, as confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electronic band structure calculations reveal direct and indirect bandgaps in the visible range, making these materials suitable for efficient light absorption in solar cells. The presence of organic cations in the hybrid structure enhances charge carrier mobility and reduces recombination losses, as evidenced by photoluminescence (PL) and time-resolved spectroscopy. Optical absorption measurements demonstrate strong absorption coefficients in the ultraviolet-visible (UV-Vis) region, highlighting their potential for photovoltaic applications. Additionally, the thermal stability and defect tolerance of K2(Sn,Pt,Te)Br6 perovskites are investigated, showing excellent resistance to environmental degradation. Our findings suggest that these hybrid hexahalometallate double perovskites are promising candidates for next-generation solar energy technologies, offering a pathway toward high-efficiency, low-cost, and stable photovoltaic devices.

Citation

MohamedAmine GHEBOULI , karim BOUFERRACHE , ,(2024-05-08), Hybrid organic-inorganic K2(Sn,Pt,Te)Br6 hexahalometallate single crystals double perovskites semiconducting materials for solar energy applications,The Second International Conference on Electrochemical Sciences and Technology Certificate of Participation "ICEST 2024",Setif 1 University-Ferhat ABBAS, ALGERIA Faculty of Technology

The Quaternary Heusler alloys CoFeXAs (X = Cr, Mn and V) fully spin-polarized with half-metallic stability, show low direct band gap, high absorption in the ultraviolet light, high spin polarization and adequate Seebeck coefficient. CoFeCrAs, CoFeMnAs and CoFeVAs have an integer magnetic moment of 4 μB, 5 μB and 3 μB according to the Slater-Pauling rule. The obtained minimal energy favors the type I CoFeVAs alloy over the type III CoFeCrAs and CoFeMnAs alloys. For CoFeCrAs and CoFeMnAs alloys, there is no band gap close to the Fermi level in the minority-spin, suggesting that they are direct Г–Г band gap semiconductors. Three-dimensional Co, Fe, and Mn atoms hybridized strongly, with little input from V and As atoms. Co, Fe, Cr, and Mn all have parallel magnetic moments, which results in ferromagnetic interactions between these atoms and gives these elements their ferromagnetic character.

Citation

MohamedAmine GHEBOULI , ,(2024-05-07), Structural stability, opto-electronic, magnetic and thermoelectric properties of Half-metallic ferromagnets quaternary Heusler alloys CoFeXAs (X = Mn, Cr and V),2nd International Conference on Electrochemical Science &Technology,University Setif

Some physical properties of hexahalometallate were computed in the zinc blend structure using GGA-PBESOL. The cell constant is consistent to the experiment value quoted in the literature, where the error is 0.95% and 1%. The elastic constants of hexahalometallate compounds are significantly smaller due to their larger reticular distances, lower Coulomb forces and then they are soft and damage tolerant. The internal coordinate of Br atom in K2PtBr6 is lower than that of the same atom in K2SnBr6, and this can be explained by the fact that it is inversely proportional to the atom radius of Se and Pt. There are two major plasmonic processes, with intensities 3.7 and 1.35 located around 53.5 nm and 72.8 nm for K2SnBr6 and K2PtBr6.

Citation

MohamedAmine GHEBOULI , ,(2024-05-07), Hybrid organic–inorganic K_2 (Sn,Pt,Te)Br_6 hexahalometallate single crystals double perovskites semiconducting materials for solar energy applications,2nd International Conference on Electrochemical Science &Technology,University Setif

First-principle calculations using the Wien2k code and the GGA-mBJ exchange potential were used in the study of the thermodynamic, dynamic, chemical and elastic stability, as well as the electronic, optical and thermoelectric properties of Cs2(Sn, Pt, Te)I6. The presence of an intermediate band in Cs2(Sn, Pt, Te)I6 semiconductors confirmed by absorption peaks appeared at photon energy corresponding to the band gap enhances the efficiency of solar cells. The ideal band gap, high dielectric constants and optimal absorption make the double perovskites under study perform well in solar cells. The calculated minimum formation energy, Helmholtz free energy and phonon modes through the first Brillouin zone for the investigated Cs2(Sn, Pt, Te)I6 family confirm their thermal, thermodynamic and dynamic stability. The acoustic phonon contribution modes come from the Cs-6s and I-5p electrons, while the Pt-6s, Sn-5p, Te-5p and I-5p electrons participate in the optical phonon modes. The narrowness of the upper valence band and the band gap in the visible region for advantage this double perovskite in energy harvesting. The geometric Goldschmidt tolerance factor value between 0.8 and 1.0 and octahedral factor 0.41 indicate that double perovskite is more stable.

Citation

MohamedAmine GHEBOULI , ,(2024-05-07), Exploring the Optoelectronic, Thermal, and Thermoelectric Characteristics of Double Perovskite Semiconductors Cs2XI6 (X= (Sn, Pt, Te )for Potential Application in Intermediate-band Solar Cells.",2nd International Conference on Electrochemical Science &Technology,University Setif

Effect of functional on structural, elastic, optoelectronic and thermoelectric characteristics of semiconducting MgX2Se4 (X = Lu, Y) spinels has been realized by WIEN2k code. The lattice constant of MgY2Se4 is slightly greater than that of MgLu2Se4, and these quantities are slightly deviated from the experimental values, where the error does not exceed 1.3%. The cohesive energy proves that both spinels are chemically stable in the normal case, and this stability is more pronounced in MgLu2Y4. The large ionic radius of Lu compared to Y explains the high bulk modulus of MgY2Se4 as well as its hardness. The spinels under study have Г → Г direct band gap located between 1.178 and 1.4 eV for all the functionals, proving their semiconductor nature. Se-s, Y-d, Lu-d states in MgY2Se4 and MgLu2Se4 dominate the upper valence band, while the first conduction band located between Fermi level and 1.5 eV is empty. There is a strong coupling between Se-p–Lu-p sites for MgLu2Se4 and Se-p–Y-p states in MgY2Se4, which reflects their hybridization. The high absorption in the ultraviolet range, the band gap between 1 and 2.4 eV and the refractive index in the range of 2.29–2.61 favour these spinels as absorbers in solar cells. Peaks of all the optical quantities studied relating to the mBJ–GGA functional are shifted to the right compared with GGA and GGA+SO approximations. The thermoelectric parameters were investigated as a function of photon energy and temperature using GGA+SO functional.

Citation

MohamedAmine GHEBOULI , ,(2024-05-07), The impact of functional aspects on the structural, elastic stability, optoelectronic properties, behavior of semiconducting MgX2Se4(X = Lu, Y) spinels,2nd International Conference on Electrochemical Science &Technology,University Setif

The simulations have been carried out to study and investigate the performance of the photovoltaic J-V characteristics of triple-junction solar cells based on Cu(In,Ga)Se2 absorbers using 2D Silvaco/Atlas simulator. The triple-junction configuration was considered as a single layer of CGS on top while the CIGS single layer was separated for middle and bottom cells. The investigations for CIGS solar cell presented in this article are in close agreement with the already observed numerical and experimental data. The photovoltaic J-V characteristics for the proposed CGS/ CIGS triple-junction solar cell, such as the short-circuit current density, open-circuit voltage, fill factor and power conversion efficiency have been investigated and observed to be 13.49 mA/ cm2, 2.64 V, 86.56% and 30.85%, respectively. The proposed configuration offers improved conversion efficiency up to 33.27% at current matching point. The entire inquiry on CIGS solar cells yields a prospective idea for single and triple-junction solar cells with high efficiency.

Citation

MohamedAmine GHEBOULI , , (2024-05-01), CGS/CIGS single and triple-junction thin film solar cell: Optimization of CGS/CIGS solar cell at current matching point, Micro and Nanostructures, Vol:189, Issue:, pages:207812, ScienceDirect

In this study, we presented a novel structure for a highly sensitive surface plasmon resonance (SPR) sensor, we propose a structure which contains six layers: BK7 prism glass, Gold thin film, Silicon sheets, Gold thin film, using transition figure of merit (FOM) 16.43 RUI−1metal dichalcogenides 2D PtSe2 layer and sample medium. We have been optimizing the thickness of each layer. The highly performance parameters in this biosensor structure are provided in terms of sensitivity(S), detection accuracy (DA), quality factor (QF) and figure of merit (FOM). Here, the addition of the hybrid Silicon—PtSe2 layer between two gold films increased the sensitivity, but we observed the (DA) and (QF) is decreased. We find the full at half maximum also decreased. We investigated the effect of gold thickness. The maximum sensitivity 200°/RIU and is gained with 35 nm Gold film, 5 nm thickness Silicon and 2 nmPtSe2 layer, we can be obtained also the configuration with 60 nm Gold thin film and 3 nm thickness Silicon (6 layer) delivers a maximum sensitivity (S) of 206°/RIU with figure of merit (FOM) of 24.03 RUI−1.Our novel structure is optimized for a highly sensitive surface plasmon resonance (SPR) sensor.

Citation

MohamedAmine GHEBOULI , , (2024-04-11), Sensitivity enhancement of biosensor (SPR) with PtSe2 using Au–Si–Au thin films, Journal of Optics, Vol:11, Issue:, pages:1-9, Springer India

By first-principles calculations with density functional theory and a pseudopotential approach, the structural, electronic, and optical properties of the anhydrous 4C16H10Br2O2 Bis (2-Bromobenzoyl) Methane crystals in Pbnc (N◦60) and P21/c (N◦14) space group are investigated. All computations are determined by a generalized gradient approximation, local density approximation and an ultra-soft pseudopotential. The calculated equilibrium parameters are in good agreement with their available experimental data. This calculation shows that the GGA/PW91 functional overestimate the lattice constant, unlike the LDA/CA-PZ. The Br–C bond distance of 1.856 (1.902) Å is comparable with experimental value of 1.901 (1.896) Å in Pbnc (P21/c) space groups. The direct band gap nature is obtained for both space groups Pbnc and P21/c, since the maximum of the valence band and the minimum of the conduction band are both situated at the YA center.

Citation

MohamedAmine GHEBOULI , , (2024-03-01), Prediction study of structural, electronic and optical properties of 4C16H10Br2O2 Bis (m-bromobenzoyl) methane crystals, Biochemistry and Biophysics Reports, Vol:37, Issue:, pages:101601, ScienceDirect

We use an ab-initio approach to analyze the structural, electronic band structure, and thermoelectric properties of titanium dioxide (TiO2 in rutile phase), and we then use rutile-TiO2 nanoparticles to determine its effects on solgel-produced polyvinyl alcohol/silicon dioxide (PVA/SiO2) hybrid films. The synthesis of hybrid films involved the incorporation of 1 % rutile-TiO2 nanoparticles in the PVA/SiO2 matrix. The thermoelectric properties of the resulting hybrid films were characterized by Seebeck coefficient measurements, as well as electrical and thermal conductivities. The synthesis of PVA/SiO2/Nano-TiO2 films was accomplished with success. The chemical bonds have amply demonstrated that the PVA backbone is connected to the (SiO2-TiO2) network. TGA testing indicates that hybrid films are more resistant to higher temperatures than pure PVA films. SiO2 nanoparticles reveal more effective loading to improve dielectric characteristics compared to TiO2. The best results are obtained in cases of mechanical, thermal and electrical insulation when both nanofillers are integrated into the polymer matrix. The findings show that the thermoelectric performance of PVA/SiO2 hybrid films is improved by the addition of (1 %) rutile-TiO2 nanoparticles in the rutile phase. This study provides insights into the potential applications of rutile-TiO2 nanoparticles in enhancing the thermoelectric properties of hybrid materials and opens up avenues for further research in this area, and contributes to the growing body of knowledge on enhancing the thermoelectric properties of materials by incorporating rutile-TiO2 nanoparticles into hybrid films synthesized by the sol-gel method.

Citation

MohamedAmine GHEBOULI , , (2024-02-07), Physical properties of rutile-TiO2 Nanoparticles and effect on PVA/SiO2 hybrid films synthesized by sol-gel method, High Energy Density Physics, Vol:52, Issue:, pages:101122, ScienceDirect

The goal of this study is based on the determination of the half-metallic ferromagnetic features of V-doped Cu2O alloys (Cu2(1-x)V2xO (x = 0, 0.25, 0.50, 0.75 and 1)) using both GGA + U and TB-mBJ-GGA approximations (GGA: the generalized gradient approximation) within the accurate full potential linearized augmented plane wave plus local orbitals (FP-LAPW + lo) method implemented in the WIEN2k package. The structural properties are computed by using the GGA approximation in order to find the equilibrium structural parameters of each alloy, such as: lattice parameter, bulk modulus and its first-pressure derivative. The electronic properties calculated by TB-mBJ-GGA and GGA + U approximations show the complete half-metallicity of Cu1.50V0.50O, CuVO, Cu0.50V1.50O and V2O alloys, in fact, all the half-metallic gaps (EHM) of the compete half-metals are given in this study. The magnetic properties of the studied alloys show that the majority of the total magnetic moment (MTot) comes from the V atom with small contributions from Cu atom and the interstitial zone. The N0α and N0β exchange-splitting constants are given in order to analyze the contributions to conduction and valence bands during the exchange and splitting process. Furthermore, the hybridization between the 2p-O and 3d-V states (pd hybridization) is the cause for the appearance of feeble magnetic moments on the non-magnetic Cu and O sites and the reduction of the atomic magnetic moment of the V atom.

Citation

MohamedAmine GHEBOULI , , (2024-02-01), Half-metallic ferromagnetic features of V-doped Cu2O alloys: TB-mBJ and DFT + U insights, Results in Physics, Vol:57, Issue:, pages:107368, ScienceDirect

Structural, elastic, mechanical and electronic properties of pure and zinc-doped SrTiO3 at the concentration in the range (1–10%) are studied by first-principles calculations. The structural parameters of synthesized compounds agree well with the standard data depicting the growth of stable compounds. A slight obvious increase in the lattice constant of 3.9245Å is observed in Zn-doped SrTiO3 due to the deviation of the atomic radii of Zn and Ti. Elastic constants and mechanical parameters of SrTiO3 are closer to their available theoretical and experimental data. The investigated compounds exhibit brittle behavior for all Zn ratios. The doping zinc concentration reduces the indirect band gap value. The doping concentration 2%, gives a band gap value closer to the experimental one. The band gap of pure SrTiO3 is 1.827eV and after doping with Zn for concentration from 1% to 10%, the optimized values are 1.970, 1.886, 1.802, 1.718, 1.635, 1.552, 1.470, 1.389, 1.310, 1.231 and 1.154eV.

Citation

MohamedAmine GHEBOULI , karim BOUFERRACHE , F Benlakhdar, Z Zerrougui, , (2024-01-10), Structural, elastic, mechanical and optoelectronic properties of zinc-doped SrTiO3 perovskite compounds, Modern Physics Letters B, Vol:38, Issue:1, pages:2350200, World Scientific Publishing Company

The main objective of this research is the explanation of the replacement of feldspar limestone imported from Spain with recycled automotive glass, in order to reduce waste and promote environmental sustainability. Details and e®orts of making porcelain ceramics from local raw materials such as quartz, kaolin and glass are also given. Replacing the feldspar with reclaimed automotive glass shows the e®ect of the Na2O and CaO solvents contained in the glass on the sintering and crystallization of the studied porcelain. The results showed that the added glass contributes to the reduction of the density and the acceleration of the sintering process, by occupying the sites of the open spaces, observed in the samples not containing feldspars. By reaching a nonporous ratio at a temperature of 1000
C, the melting of the material is accelerated due to the dissolved oxides it contains, in addition to the linear shrinkage rate in samples that contain a lot of glass reaching the normal level of porcelain (about 12%) at low temperature compared to ordinary porcelain.

Citation

MohamedAmine GHEBOULI , , (2024-01-01), Sustainable porcelain ceramics production using local raw materials and recycled automotive glass, Modern Physics Letters B, Vol:9, Issue:12, pages:2450064, World Scienti¯c Publishing Company

The crystal structure, mechanical, electronic, optical and thermoelectric characteristics of Cs2MCl6 (M = Se, Sn, Te and Ti) cubic double perovskites are studied within GGA, GGA-mBJ and EV-GGA functionals. The M − Cl bond lengths are shorter and especially in Cs2TiCl6 double perovskite, which reflects the strong interaction between M and Cl atoms and this is correlated with its better chemical stability. The negativity of formation energy and Helmholtz free energy and no imaginary phonon modes throughout the Brillouin zone confirm the thermal, thermodynamic and dynamical stability of these double perovskites. Semiconductors Cs2MCl6 (M = Se, Sn, Te and Ti) double perovskites with flat conduction and valence bands, and an indirect band gap are p-type carriers. A high Seebeck coefficient, adequate ZT values and non-toxicity make these compounds attractive for thermoelectric applications at high temperature and spintronic technology. The empty first conduction band corresponds to their band gap, and the transition occurs from Cl-p to (Se-p, Sn-p, Te-p and Ti-d). The high static dielectric constant and the intense peak of the real part in the ultraviolet energy range favor less the recombination rate of charge carriers and their use in optoelectronic devices. The indirect band gap, high absorption in ultraviolet energy, high static refractive index make these cubic double perovskites as ideal materials for solar cell applications.

Citation

MohamedAmine GHEBOULI , , (2024-01-01), Crystal structure, mechanical, electronic, optical and thermoelectric characteristics of Cs2MCl6 (M = Se, Sn, Te and Ti) cubic double perovskites, Results in Physics, Vol:56, Issue:, pages:107138, ScienceDirect

The Quaternary Heusler alloys CoFeXAs (X = Cr, Mn and V) fully spin-polarized with half-metallic stability, show low direct band gap, high absorption in the ultraviolet light, high spin polarization and adequate Seebeck coefficient. CoFeCrAs, CoFeMnAs and CoFeVAs have an integer magnetic moment of 4 μB, 5 μB and 3 μB according to the Slater-Pauling rule. The obtained minimal energy favors the type I CoFeVAs alloy over the type III CoFeCrAs and CoFeMnAs alloys. For CoFeCrAs and CoFeMnAs alloys, there is no band gap close to the Fermi level in the minority-spin, suggesting that they are direct Г–Г band gap semiconductors. Three-dimensional Co, Fe, and Mn atoms hybridized strongly, with little input from V and As atoms. Co, Fe, Cr, and Mn all have parallel magnetic moments, which results in ferromagnetic interactions between these atoms and gives these elements their ferromagnetic character.

Citation

MohamedAmine GHEBOULI , , (2024-01-01), Structural stability, opto-electronic, magnetic and thermoelectric properties of half-metallic ferromagnets quaternary Heusler alloys CoFeXAs (X = Mn, Cr and V), solid State Communication, Vol:377, Issue:, pages:115366, ScienceDirect

The crystal structure, mechanical, electronic, optical and thermoelectric characteristics of Cs2MCl6 (M = Se, Sn, Te and Ti) cubic double perovskites are studied within GGA, GGA-mBJ and EV-GGA functionals. The M − Cl bond lengths are shorter and especially in Cs2TiCl6 double perovskite, which reflects the strong interaction between M and Cl atoms and this is correlated with its better chemical stability. The negativity of formation energy and Helmholtz free energy and no imaginary phonon modes throughout the Brillouin zone confirm the thermal, thermodynamic and dynamical stability of these double perovskites. Semiconductors Cs2MCl6 (M = Se, Sn, Te and Ti) double perovskites with flat conduction and valence bands, and an indirect band gap are p-type carriers. A high Seebeck coefficient, adequate ZT values ​​and non-toxicity make these compounds attractive for thermoelectric applications at high temperature and spintronic technology. The empty first conduction band corresponds to their band gap, and the transition occurs from Cl-p to (Se-p, Sn-p, Te-p and Ti-d). The high static dielectric constant and the intense peak of the real part in the ultraviolet energy range favor less the recombination rate of charge carriers and their use in optoelectronic devices. The indirect band gap, high absorption in ultraviolet energy, high static refractive index make these cubic double perovskites as ideal materials for solar cell applications.

Citation

karim BOUFERRACHE , MohamedAmine GHEBOULI , , (2024-01-01), Crystal structure, mechanical, electronic, optical and thermoelectric characteristics of Cs2MCl6 (M= Se, Sn, Te and Ti) cubic double perovskites, Results in Physics, Vol:56, Issue:56, pages:107138, Elsevier

By first-principles calculations with density functional theory and a pseudopotential approach, the structural, electronic, and optical properties of the anhydrous 4C16H10Br2O2 Bis (2-Bromobenzoyl) Methane crystals in Pbnc (N◦60) and P21/c (N◦14) space group are investigated. All computations are determined by a generalized gradient approximation, local density approximation and an ultra-soft pseudopotential. The calculated equilibrium parameters are in good agreement with their available experimental data. This calculation shows that the GGA/PW91 functional overestimate the lattice constant, unlike the LDA/CA-PZ. The Br–C bond distance of 1.856 (1.902) Å is comparable with experimental value of 1.901 (1.896) Å in Pbnc (P21/c) space groups. The direct band gap nature is obtained for both space groups Pbnc and P21/c, since the maximum of the valence band and the minimum of the conduction band are both situated at the YA center.

Citation

MohamedAmine GHEBOULI , , (2023-12-05), Prediction study of structural, electronic and optical properties of 4C16H10Br2O2 Bis (m-bromobenzoyl) methane crystals, Biochemistry and Biophysics Reports, Vol:37, Issue:37, pages:101601, sciencediret

By first-principles calculations with density functional theory and a pseudopotential approach, the structural, electronic, and optical properties of the anhydrous 4C16H10Br2O2 Bis (2-Bromobenzoyl) Methane crystals in Pbnc (N°60) and P21/c (N°14) space group are investigated. All computations are determined by a generalized gradient approximation, local density approximation and an ultra-soft pseudopotential. The calculated equilibrium parameters are in good agreement with their available experimental data. This calculation shows that the GGA/PW91 functional overestimate the lattice constant, unlike the LDA/CA-PZ. The Br–C bond distance of 1.856 (1.902) Å is comparable with experimental value of 1.901 (1.896) Å in Pbnc (P21/c) space groups. The direct band gap nature is obtained for both space groups Pbnc and P21/c, since the maximum of the valence band and the minimum of the conduction band are both situated at the YA center.

Citation

MohamedAmine GHEBOULI , karim BOUFERRACHE , R. Boudissa, Z. Zerrougui, , (2023-12-05), Prediction study of structural, electronic and optical properties of 4C 16 H 10 Br 2 O 2 Bis (m-bromobenzoyl) methane crystals, Biochemistry and Biophysics Reports, Vol:37, Issue:, pages:101601, Elsevier

Ab-initio simulations based on density functional theory as contained in the WIEN2k code using GGA, GGA+U, and mBJ approximations were used to perform the calculations. The energy of cohesion is minimal for FeMnCrSb, indicating that it is the most stable structure, with a lattice constant of 5.95 Å and 6.2184 Å for GGA and GGA+U. The ferromagnetic state is less stable than ferrimagnetic states in all studied quaternary Heusler. All the band structures are metallic, with the exception of the spin up case using GGA+U and mBJ approaches, where the semiconducting character is predicted. The amount of absorption and band gap validates the candidature of CoFeCrAl, CoFeMnSi, CoMnCrSi, and FeMnCrSb as absorber materials for photovoltaic devices. The high values of 0.8, 0.9, 0.95 and 1 for figure of merit (ZT) at 300 K were obtained for CoFeMnSi, CoFeCrAl, CoMnCrSi, and FeMnCrSb allowing their use in spintronic and thermoelectric applications. The resistivity of studied quaternary alloys is little sensitive to the temperature, while the electronic conductivity and power factor are proportional to the temperature

Citation

MohamedAmine GHEBOULI , ,(2023-12-02), the structural properties, optoelectronic and magnetic behaviour of CoFeMtAs quaternary heusler alloy,First national conférence on physics and its application,Bousaada

The goal of this study is based on the determination of the half-metallic ferromagnetic features of V-doped Cu2O alloys (Cu2(1-x)V2xO (x = 0, 0.25, 0.50, 0.75 and 1)) using both GGA + U and TB-mBJ-GGA approximations (GGA: the generalized gradient approximation) within the accurate full potential linearized augmented plane wave plus local orbitals (FP-LAPW + lo) method implemented in the WIEN2k package. The structural properties are computed by using the GGA approximation in order to find the equilibrium structural parameters of each alloy, such as: lattice parameter, bulk modulus and its first-pressure derivative. The electronic properties calculated by TB-mBJ-GGA and GGA + U approximations show the complete half-metallicity of Cu1.50V0.50O, CuVO, Cu0.50V1.50O and V2O alloys, in fact, all the half-metallic gaps (EHM) of the compete half-metals are given in this study. The magnetic properties of the studied alloys show that the majority of the total magnetic moment (MTot) comes from the V atom with small contributions from Cu atom and the interstitial zone. The N0α and N0β exchange-splitting constants are given in order to analyze the contributions to conduction and valence bands during the exchange and splitting process. Furthermore, the hybridization between the 2p-O and 3d-V states (p- d hybridization) is the cause for the appearance of feeble magnetic moments on the non-magnetic Cu and O sites and the reduction of the atomic magnetic moment of the V atom.

Citation

MohamedAmine GHEBOULI , , (2023-11-30), Half-metallic ferromagnetic features of V-doped Cu2O alloys: TB-mBJ and DFT + U insights, Results in Physics, Vol:57, Issue:57, pages:107368, Elsevier

In the pursuit of sustainable porcelain production, this research examines the potential of using recovered automotive glass as a substitute for traditional feldspar, specifically feldspar imported from Spain. Porcelain samples were sintered at different temperatures and with varied proportions of automotive glass. The crystalline phases formed post-sintering were determined through X-ray diffraction and quantified by dissolving the porcelain in concentrated hydrofluoric acid. Results revealed that the inclusion of automotive glass, owing to its dissolved oxide content, accelerated the porcelain melting process and led to an increase in the vitreous phase. Notably, anorthite phases became dominant and mullite formation was evident at 1100 ◦C, stabilizing in samples G00 and G10, and then increasing at 1200 ◦C due to the emergence of secondary mullite. This secondary mullite forms from the residual silica after the primary mullite formation and the aluminium in the feldspars, which is about 17 %. For samples G20 and G30, only primary mullite was observed due to the decreased aluminium content resultant from feldspar replacement by glass. These findings underscore the viability of automotive glass in porcelain production, providing a sustainable and effective alternative to feldspar

Citation

MohamedAmine GHEBOULI , , (2023-11-23), Effect of temperature and glass content on crystalline phases in porcelain sintered with recovered automotive glass, Heliyon, Vol:9, Issue:9, pages:e22554, Elseier

The crystal structure, mechanical, electronic, optical and thermoelectric characteristics of Cs2MCl6 (M = Se, Sn, Te and Ti) cubic double perovskites are studied within GGA, GGA-mBJ and EV-GGA functionals. The M − Cl bond lengths are shorter and especially in Cs2TiCl6 double perovskite, which reflects the strong interaction between M and Cl atoms and this is correlated with its better chemical stability. The negativity of formation energy and Helmholtz free energy and no imaginary phonon modes throughout the Brillouin zone confirm the thermal, thermodynamic and dynamical stability of these double perovskites. Semiconductors Cs2MCl6 (M = Se, Sn, Te and Ti) double perovskites with flat conduction and valence bands, and an indirect band gap are p-type carriers. A high Seebeck coefficient, adequate ZT values and non-toxicity make these compounds attractive for thermoelectric applications at high temperature and spintronic technology. The empty first conduction band corresponds to their band gap, and the transition occurs from Cl-p to (Se-p, Sn-p, Te-p and Ti-d). The high static dielectric constant and the intense peak of the real part in the ultraviolet energy range favor less the recombination rate of charge carriers and their use in optoelectronic devices. The indirect band gap, high absorption in ultraviolet energy, high static refractive index make these cubic double perovskites as ideal materials for solar cell application

Citation

MohamedAmine GHEBOULI , , (2023-11-23), Crystal structure, mechanical, electronic, optical and thermoelectric characteristics of Cs2MCl6 (M = Se, Sn, Te and Ti) cubic double perovskite, Results in Physics, Vol:56, Issue:56, pages:107183, elsevier

The Quaternary Heusler alloys CoFeXAs (X = Cr, Mn and V) fully spin-polarized with half-metallic stability, show low direct band gap, high absorption in the ultraviolet light, high spin polarization and adequate Seebeck coefficient. CoFeCrAs, CoFeMnAs and CoFeVAs have an integer magnetic moment of 4 μB, 5 μB and 3 μB according to the Slater-Pauling rule. The obtained minimal energy favors the type I CoFeVAs alloy over the type III CoFeCrAs and CoFeMnAs alloys. For CoFeCrAs and CoFeMnAs alloys, there is no band gap close to the Fermi level in the minority-spin, suggesting that they are direct Г–Г band gap semiconductors. Three-dimensional Co, Fe, and Mn atoms hybridized strongly, with little input from V and As atoms. Co, Fe, Cr, and Mn all have parallel magnetic moments, which results in ferromagnetic interactions between these atoms and gives these elements their ferromagnetic character.

Citation

MohamedAmine GHEBOULI , , (2023-10-24), Structural stability, opto-electronic, magnetic and thermoelectric properties of half-metallic ferromagnets quaternary Heusler alloys CoFeXAs (X = Mn, Cr and V), Solid State Communications, Vol:377, Issue:377, pages:115366, elsevier

The main objective of this research is the explanation of the replacement of feldspar limestone imported from Spain with recycled automotive glass, in order to reduce waste and promote environmental sustainability. Details and efforts of making porcelain ceramics from local raw materials such as quartz, kaolin and glass are also given. Replacing the feldspar with reclaimed automotive glass shows the effect of the Na2O and CaO solvents contained in the glass on the sintering and crystallization of the studied porcelain. The results showed that the added glass contributes to the reduction of the density and the acceleration of the sintering process, by occupying the sites of the open spaces, observed in the samples not containing feldspars. By reaching a nonporous ratio at a temperature of 1000∘C, the melting of the material is accelerated due to the dissolved oxides it contains, in addition to the linear shrinkage rate in samples that contain a lot of glass reaching the normal level of porcelain (about 12%) at low temperature compared to ordinary porcelain.

Citation

MohamedAmine GHEBOULI , , (2023-10-13), Sustainable porcelain ceramics production using local raw materials and recycled automotive glass, Modern Physics Letters B, Vol:5, Issue:5, pages:2450064, World Scientific Publishing Company

Zinc monochalcogenides, specifically ZnS serve as exemplary representatives of II-VI semiconductors and have the ability to adopt either zinc-blende (ZnX-z) or wurtzite (ZnX-w) crystal structures. Notably, ZnX-z phases exhibit optical isotropy, while ZnX-w phases display anisotropy, with the c-axis serving as the polar axis. ZnS featuring a wide direct band gap of approximately 3.37 eV at room temperature, emerges as a quintessential semiconductor employed extensively in optoelectronic applications. Furthermore, ZnS exhibits transparency within the visible light spectrum and possesses the added advantage of environmental friendliness, attributed to the abundant presence of zinc in the Earth's crust. Among the family of IIB-VIA compounds, namely ZnS, this material crystallizes in the cubic zinc-blende structure under ambient pressure, boasting direct energy band gaps. Notably, these wide band-gap semiconductors are of paramount interest due to their capability to emit light even at room temperature. Utilizing computational tools such as CASTEP offers a robust means for designing and enhancing these materials, facilitating the development of advanced optoelectronic devices. In this study, we delved into the electronic structure and optical characteristics of ZnS systems, employing first principles through the ultra-smooth pseudopotential approach of density functional theory and the generalized gradient approximation method implemented with CASTEP. Our investigation yielded the following findings: The network parameters exhibited varying values, making it feasible to deposit these materials on different substrates. The binary alloy holds particular interest due to its wide bandgap 2.698 eV for ZnS. The results obtained for the structural, physical, and optical properties closely align with existing theoretical and experimental data, affirming the accuracy of our calculation methodology. The properties of pure ZnS materials suggest significant potential for use in solar cells.

Citation

MohamedAmine GHEBOULI , ,(2023-10-10), Comprehensive investigation of ZnS: Structural properties, Elastic constants and their crucial role in environmental protection and clean energy production,,The second International conference of nanotechnology for environmental protection and clean energy production ICNEP-2023,Freres Mentouri University - Constantine I,Mentouri University - Constantine I

The structural, electronic, optical and thermodynamic properties of SrxCa1-xO, BaxSr1-xO and BaxCa1-xO ternary alloys in NaCl phase were studied using pseudo-potential plane-wave method within the density functional theory. We modeled the alloys at some selected compositions with ordered structures described in terms of periodically repeated supercells. The dependence of the lattice parameters, band gaps, dielectric constants, refractive indices, Debye temperatures, mixing entropies and heat capacities on the composition x were analyzed for x = 0, 0.25, 0.50, 0.75 and 1. The lattice constant for SrxCa1-xO and BaxSr1-xO exhibits a marginal deviation from the Vegard’s law, while the BaxCa1-xO lattice constant exhibits an appreciable upward bowing. A strong deviation of the bulk modulus from linear concentration dependence was observed for the three alloys. The microscopic origins of the gap bowing were detailed and explained. The composition dependence of the dielectric constant and refractive index was studied using different models. The thermodynamic stability of these alloys was investigated by calculating the phase diagram. The thermal effect on some macroscopic properties was investigated using the quasi-harmonic Debye model. There is a good agreement between our results and the available experimental data for the binary compounds which may be a support for the results of the ternary alloys reported here for the first time.

Citation

MohamedAmine GHEBOULI , ,(2023-10-09), Structural, electronic, optical and thermodynamic properties of SrxCa1-xO, BaxSr1-xO and BaxCa1-xO alloys,Second international conférence of nanotechnology for environmental protection ans clean energy protection,University mentouri constantine 1

The purpose of this research is to investigate the structural, electronic, and optical properties of ZnX compounds, particularly those with X = Te, S, and O, which have direct bandgaps that make them optically active. To gain a better understanding of these compounds and their related properties, we conducted detailed calculations using density functional theory (DFT) and the CASTEP program, which uses the generalized gradient approximation (GGA) to estimate the cross-correlation function. Our results for lattice modulus, energy bandgap, and optical parameters are consistent with both experimental data and theoretical predictions. The energy bandgap for all compounds is relatively large due to an increase in s-states in the valence band. Our findings suggest that the optical transition between (O - S - Te) - p states in the highest valence band and (Zn - S - O) - s states in the lowest conduction band is shifted to the lower energy band. Therefore, ZnX compounds (X = Te, S and O) are a promising option for optoelectronic device applications, such as solar cell materials

Citation

MohamedAmine GHEBOULI , , (2023-06-07), AB-INITIO STUDY OF STRUCTURAL, ELECTRONIC AND OPTICAL PROPERTIES OF ZnX (X = Te, S and O): APPLICATION TO PHOTOVOLTAIC SOLAR CELLS, EAST EUROPEAN JOURNAL OF PHYSICS., Vol:3, Issue:3, pages:413-433, Springer

Cet ouvrage qui comprend des exercices corrigés a été réalisé dans le but de faciliter la compréhension de la structure de la matière et les liaisons chimiques. Ce document est destiné principalement aux étudiants de la première année des filières Sciences de la Matière (SM), Sciences Techniques (ST), et Sciences de la Nature et de la Vie (SVI). Cette édition d'exercices corrigés permet aux étudiants de ces filières d’acquérir une méthodologie adéquate pour résoudre les problèmes de la chimie de l’atome. Ce manuscrit se compose de cinq parties, où on étudie principalement la structure de l'atome, les modèles quantique et ondulatoire de l'atome de Bohr, la classification périodique et la structure électronique des éléments ainsi que leurs propriétés et enfin les liaisons chimiques entre atomes et molécules. Chaque chapitre comprend une série d’exercices choisie pour son intérêt et sa diversité. On reporte aussi le corrigé détaillé de cette série afin que les étudiants puissent assimiler le cours de cette matière. On propose dans le premier chapitre des exercices de connaissances générales sur la structure de l’atome, sur les isotopes et les défauts de masse. Le second chapitre est consacré au calcul des différents paramètres de l’atome d’hydrogène et des ions hydrogénites selon le modèle de Bohr. L'étude des différentes séries spectrales de l’atome d’hydrogène est également bien détaillée. Dans le troisième chapitre, on traite le modèle ondulatoire de l’atome qui comprend la relation de Louis De Broglie, l'équation de Schrödinger, les fonctions d’ondes et les orbitales atomiques. On détermine aussi les structures électroniques des éléments en utilisant les règles de remplissage des électrons dans les différentes couches et sous-couches de l’atome. Les exercices que contient le chapitre quatre servent à déterminer la structure électronique d’un atome et son numéro atomique suivant son classement dans le tableau périodique. Ces exercices permettent aussi de trouver le groupe ou la période auxquels appartient l’atome. Le dernier chapitre traite des exercices d'application sur les différentes liaisons chimiques possibles entre les atomes et molécules. Mon souhait est que ce modeste travail améliore l'encadrement et la formation dans notre Université et qu'il sera d'une grande importance à nos étudiants pour acquérir une base solide en chimie de la matière.

Citation

MohamedAmineGHEBOULI , ,(2023-05-09); structure de la matière exercices corriges,Mohamed Boudiaf Msila,

Ab-initio simulations based on density functional theory as contained in the WIEN2k code using GGA, GGA+U, and mBJ approximations were used to perform the calculations. The energy of cohesion is minimal for FeMnCrSb, indicating that it is the most stable structure, with a lattice constant of 5.95 Å and 6.2184 Å for GGA and GGA+U. The ferromagnetic state is less stable than ferrimagnetic states in all studied quaternary Heusler. All the band structures are metallic, with the exception of the spin up case using GGA+U and mBJ approaches, where the semiconducting character is predicted. The amount of absorption and band gap validates the candidature of CoFeCrAl, CoFeMnSi, CoMnCrSi, and FeMnCrSb as absorber materials for photovoltaic devices. The high values of 0.8, 0.9, 0.95 and 1 for figure of merit (ZT) at 300 K were obtained for CoFeMnSi, CoFeCrAl, CoMnCrSi, and FeMnCrSb allowing their use in spintronic and thermoelectric applications. The resistivity of studied quaternary alloys is little sensitive to the temperature, while the electronic conductivity and power factor are proportional to the temperature.

Citation

MohamedAmine GHEBOULI , , (2023-01-13), Stability, electronic band structure, magnetic, optical and thermoelectric properties of CoXCrZ (X = Fe, Mn and Z = Al, Si) and FeMnCrSb quaternary Heusle, Chinese Journal of Physics, Vol:81, Issue:81, pages:303-324, Elseier

Special quasi-random structure (SQS) was used to investigate the structural, electronic, and optical characteristics of the binary and ternary beryllium chalcogenide alloys. The computations were performed using the pseudopotential technique. The GGA-WC scheme was applied to study the structural and optical features of these present alloys, while the HSE06 hybrid functional was used to correct the underestimation of the electronic band structure. The optimized lattice constants and bulk modulus demonstrate a non-linear tendency with increasing x concentration. The phase transition may occur for all ternary alloys at x  = 0.5 with the orthorhombic assumed crystal system. The ternary alloys of have an indirect band gap, while manifest a metallic demeanor using HSE06 formalism. The optical spectra were computed and discussed in detail. Furthermore, the thermodynamic stability of the studied compounds was examined using the miscibility critical temperature.

Citation

MohamedAmine GHEBOULI , Mohammed M.Obeid, R.Khenata, Majid M.Shukur, Shaker J.Edrees, Shakeel Ahmad, A. Bouhemadou, Hamad RahmanJappor, , (2019), Electronic band structure, thermodynamics and optical characteristics of BeO1−xAx(A = S, Se, Te) alloys: Insights from ab initio study, Chemical Physics, Vol:526, Issue:, pages:110414, sciencedirect

We studied the ternary acetylides A2MC2 (A = Na, K) and (M = Pb, Pt) with trigonal structures by using the density functional theory (DFT) as implemented in the CASTEP code. The calculated lattice parameters and atomic fractional coordinates were in agreement with previous calculations and experimental data. A set of isotropic elastic parameters and related properties, namely the module and shear moduli, Young’s modulus, Poisson’s ratio, average sound velocity and Debye temperature were numerically estimated in the frame work of the Voigt-Reuss-Hill approximation. The absorption, energy-loss and dielectric function were calculated. We studied the main contribution to the optical spectra from the transition from the top four valence bands towards the lower three first one of conduction based on the electronic structures.

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MohamedAmine GHEBOULI , Messaoud Fatmi, Tayeb CHIHI, Brahim Ghebouli, , (2019), Study of the Structural, Elastic, Electronic and Optical Properties of the Ternary Acetylides A2MC2 (A = Na, K) and (M = Pb, Pt), Journal- Korean Physical Society, Vol:75, Issue:9, pages:678-684, Springer

We derived the chemical compositions and the micro hardness of the two studied steels Fe20Mn5Cr and Fe9S28Mn. The contamination of these two compounds by oxygen gives the series M2O3 (M = Fe, Cr, Al). Rhombohedral crystal structure of these compounds was determined by means of the X-rays diffraction. First principles calculations were performed to investigate structural, elastic and mechanical properties of M2O3 (M = Fe, Cr, Al) compounds at equilibrium pressure. Fe2O3 and Cr2O3 are classified as ductile materials, while Al2O3 is brittle. The Debye temperature, the elastic wave velocities and the integration of elastic wave velocities in various directions of the single crystal were obtained. All these compounds are elastically and chemically stable. The calculated elastic constants are in good agreement with the experiment values in the approximation of the gradient generalized for the correlation and exchange potential. We calculated the partial and total densities of states PDOD and TDOS for M2O3 (M = Fe, Cr, Al) compounds. As a result, electronic bands, DOS at the Fermi level, were obtained for the first time especially for Fe2O3 and Cr2O3.

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MohamedAmine GHEBOULI , Tayeb CHIHI, Messaoud Fatmi, Brahim GHEBOULI, , (2019), Structural, elastic, thermoelastic and electronic properties of M2O3 (M = Cr, Fe, Al) compounds: Experimental and theoretical study, Results in Physics, Vol:12, Issue:, pages:725, Sciencedirect.

The lead free halides double perovskites show a particular interest in the conception of perovskites solar cells. We predicted the lattice constant and the atomic Wycko position of these lead free halide double perovskites Cs2AgBiX6 (X = Br, Cl) under pressure effect. The alloying ability of crystal, elastic constants and related parameters, electronic and optical properties have been studied using pseudo potential plane wave method based on the density functional theory. The investigated lead free halide double perovskites Cs2AgBiX6 (X = Br, Cl) show a weaker resistance to compression along the a-axis. This result also proves the existence of a directional bonding between atoms and a weaker resistance to compression along the a-axis The band structure indicates that Cs2AgBiX(X = Br, Cl) are X–L indirect gap semiconductors. Our computed bulk modulus and its pressure derivative of double perovskites Cs2AgBiX6 (X = Br, Cl) are predictions. The calculated elastic constants of Cs2AgBiX6 (X = Br, Cl) at equilibrium and under pressure effect are predictions.

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MohamedAmine GHEBOULI , Tayeb CHIHI, Brahim GHEBOULI, Messaoud Fatmi, , (2018), Study of the structural, elastic, electronic and optical properties of lead free halide double perovskites Cs2AgBiX6(X = Br, Cl), Chinese Journal of Physics, Vol:56, Issue:1, pages:323, Sciencedirect.

First principles calculations are applied in the study of FeMP (M = Ti, Zr, Hf) compounds. We investigate the structural, elastic, mechanical and electronic properties by combining first-principles calculations with the CASTEP approach. For ideal polycrystalline FeMP (M = Ti, Zr, Hf) the shear modulus, Young’s modulus, Poisson’s ratio, elastic anisotropy indexes, Pugh’s criterion, elastic wave velocities and Debye temperature are also calculated from the single crystal elastic constants. The shear anisotropic factors and anisotropy are obtained from the single crystal elastic constants. The Debye temperature is calculated from the average elastic wave velocity obtained from shear and bulk modulus as well as the integration of elastic wave velocities in different directions of the single crystal.

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MohamedAmine GHEBOULI , A.Tanto, Tayeb chihi, Mounir Reffas, Messaoud Fatmi, Brahim GHEBOULI, , (2018), Prediction study of structural, elastic and electronic properties of FeMP (M = Ti, Zr, Hf) compounds, Results in Physics, Vol:9, Issue:, pages:763, Sciencedirect.

This study investigated the effect of aging on the precipitation and kinetics of second phase Mg17Al12 in AZ91 magnesium alloy (Mg-9 wt% Al-1 wt% Zn), using X-ray diffraction, microhardness measurements and differential scanning calorimetric analysis (DSC). With the last instrument, the all samples were heated from room temperature to 400 °C, at heating rates of 10–30 °C/min. The results were supplemented by measuring the average of activation energies, using isothermal treatments by Johnson–Mehl–Avrami (JMA) methods and by non-isothermal treatments using Ozawa, Boswell, Kissinger, Mahadevan, Augis and Bennett methods, were around 67.18 and 62.02 kJ/mol. The frequency factor k0 calculated by the isothermal treatment is equal to 1.24 109 s−1. In non-isothermal treatment, the numerical factor m and the Avrami parameter n is estimated to be approximately equal to 3 and 2.79 respectively. This value corresponding that the bulk nucleation with a constant number of nuclei was dominant in three-dimensional (polyhedron) controlled by interface reaction.

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MohamedAmine GHEBOULI , Messaoud Fatmi, A. Djemli², A. Ouali, Tayeb Chihi, H.Belhouchet, , (2018), Heat treatment and kinetics of precipitation of β-Mg17Al12 phase in AZ91 alloy, Results in Physics, Vol:10, Issue:, pages:693, Sciencedirect.

In this paper, we present a detailed theoretical investigation on the structural, elastic, electronic and optical properties of the perovskite oxides SrThO3 and SrZrO3 by using the pseudo-potential plane wave (PP-PW) method. The computed lattice constants of SrXO3 (X = Th and Zr) are in excellent agreement with the available experimental data. SrThO3 and SrZrO3 are direct (Γ–Γ) and indirect (Γ–R) band gap semiconductors, respectively. Under pressure effect a crossover between the indirect band gap (R–Γ) and the direct band gap (Γ–Γ) curves occurs at about 35 GPa for SrZrO3, resulting in the energy minimum of direct gap (Γ–Γ) for this compound. The covalence in the Zr–O and Th–O bonds arises due to the hybridization between O–p and Zr–d (Th–d) states. Under pressure effect, the threshold energy becomes slightly greater (smaller) for SrZrO3 (SrTO3) for 3.21 (2.28) eV and the main peaks are shifted towards higher energies. Although the positions of all peaks shifted under pressure, they still have the same type as those at zero pressure, with decreasing the intensity of the main peaks.

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MohamedAmine GHEBOULI , Tayeb CHIHI, F. Dahman, Brahim GHEBOULI, Messaoud Fatmi, Tarek Seddik, A. Abdiche, Rabah Khenata, , (2018), Structural, elastic and optoelectronic properties of Sr-based perovskite-type oxides SrXO3 (M = Th, Zr) via first-principles calculations, Chinese Journal of Physics, Vol:56, Issue:4, pages:1515, Sciencedirect.

The structural, electronic, optical and thermodynamic properties of SrxCa1−xO, BaxSr1−xO and BaxCa1−xO ternary alloys in NaCl phase were studied using pseudo-potential plane-wave method within the density functional theory. We modeled the alloys at some selected compositions with ordered structures described in terms of periodically repeated supercells. The dependence of the lattice parameters, band gaps, dielectric constants, refractive indices, Debye temperatures, mixing entropies and heat capacities on the composition x were analyzed for x = 0, 0.25, 0.50, 0.75 and 1. The lattice constant for SrxCa1−xO and BaxSr1−xO exhibits a marginal deviation from the Vegard's law, while the BaxCa1−xO lattice constant exhibits an appreciable upward bowing. A strong deviation of the bulk modulus from linear concentration dependence was observed for the three alloys. The microscopic origins of the gap bowing were detailed and explained. The composition dependence of the dielectric constant and refractive index was studied using different models. The thermodynamic stability of these alloys was investigated by calculating the phase diagram. The thermal effect on some macroscopic properties was investigated using the quasi-harmonic Debye model. There is a good agreement between our results and the available experimental data for the binary compounds which may be a support for the results of the ternary alloys reported here for the first time.

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MohamedAmine GHEBOULI , ,(2018), Structural, electronic, optical and thermodynamic properties of SrxCa1−xO, BaxSr1−xO and BaxCa1−xO alloys,4 TH INTERNATIONAL CONFERENCE ON ADVANCES IN MECHANICAL ENGINEERING,Yildiz university

Ce polycopié est destiné aux étudiants de première année du système Licence-Master-Doctorat (L.M.D), spécialité : Sciences et Technologie (S.T) Il comporte un rappel de cours et des exercices résolus sur les différents chapitres du module chimie 2 (thermodynamique). Le cours permet d’acquérir certaines notions fondamentales en thermodynamique facilitant ainsi une meilleure maitrise des concepts fondamentaux appliqués dans le domaine d’ingénierie thermique. Le polycopié est réparti en cinque chapitres : Le premier chapitre: Généralités sur la thermodynamique avec un rappel de notions mathématiques ainsi que quelques définitions en rapport avec la thermodynamique en général. Le deuxième chapitre : Température, Chaleur, travail et Calorimétrie Le troisième chapitre : Enoncé du premier principe de la thermodynamique. Le quatrième chapitre : Applications du premier principe en thermochimie et le cinquième chapitre : Second principe de la thermodynamique.

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MohamedAmineGHEBOULI , ,(2018); Thermodynamique,Mohamed Boudiaf - M'sila -,

We studied the profiles of the micro hardness in the nuances 9SMn28, 42CrMo4 and CK45, which have a rapid decline to the depth 0.1 mm, and then slowly decrease to the value of the characteristic of the casting material. The surface layer contains mostly the iron nitrides phases FeyN (y = 1, 2, 3, 4). We use first principles to study the electronic and magnetic properties of some structural phases. We calculated the lattice parameters of all the compounds; our results show good agreement with other calculations. The estimated formation energies first show a decrease then an increase with the nitrogen content. The contribution of the PDOS is due to the Fe-3d and N-2p states in Fe(1–4)N. We used experimental and theoretical studies to determine all of the phases existing in a nitride layer.

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MohamedAmine GHEBOULI , Tayeb CHIHI, Messaoud Fatmi, Brahim GHEBOULI, Djemai .H, , (2017), Experimental and theoretical study of the structural, mechanical and electronic properties of the FeyN (y= 1, 2, 3, 4) phases, Chinese Journal of Physics, Vol:55, Issue:3, pages:674, Sciencedirect.

Using ab initio spin-polarized density functional theory calculations, the structural, elastic and thermodynamic properties of the orthorhombic and hexagonal phases of the iron carbide Fe7C3 were investigated. The calculated ground-state lattice parameters are in good agreement with the available corresponding theoretical and experimental data. The single-crystal and polycrystalline aggregate elastic constants, sound velocities, Debye temperature, brittle/ductile character and elastic anisotropy have been estimated. The calculated bulk modulus values of both considered phases are very close and are approximately equal to 262 GPa, which classifies the title compounds among the hard materials. The temperature and pressure dependencies of the unit-cell volume, bulk modulus, volume thermal expansion coefficient, isochoric and isobaric heat capacity, and Debye temperature were investigated using the quasi-harmonic Debye model.

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MohamedAmine GHEBOULI , Tayeb CHIHI, Abdelmadjid Bouhemadou, Mounir Reffas, Rabah Khenata, Brahim Ghebouli, Layachi Louail, , (2017), Structural, elastic and thermodynamic properties of iron carbide Fe7C3 phases: An ab initio study, Chinese Journal of Physics, Vol:55, Issue:3, pages:977, Sciencedirect.

Electronic band structure and lattice dynamical properties of CaxMg1−xS alloys in the rock-salt phase have been investigated. The calculations are performed in the framework of ab initio pseudo-potential approach within the generalized gradient approximation. Reasonable agreement is generally obtained between our results and the available experimental observations and previous calculations. The deviation of the alloy lattice constant and bulk modulus from linearity has been examined and discussed. Fundamental band gaps and Г–X and Г–L separations in higher-lying conduction bands are predicted. In agreement with reflectivity spectrum and recent optical absorption spectrum measurements, CaS in the rock-salt phase is found to be an indirect band-gap (Г–X). Similarly to CaS, the electronic band structure calculations showed that MgS is also an indirect band-gap (Г–X) semiconductor. However, a system transition between indirect and direct structures has been predicted in the Ca concentration range 0.12–0.83. Upon alloying the phonon modes are significantly changed showing that the longitudinal optical–transverse optical (LO–TO) splitting becomes narrower as one proceeds from pure rock-salt MgS to pure rock-salt CaS.

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MohamedAmine GHEBOULI , Hassina Choutri, Nadir Bouarissa, , (2014), Electronic structure and lattice dynamics of CaxMg1−xS in the rock-salt phase, Materials Science in Semiconductor Processing, Vol:18, Issue:, pages:71, Sciencedirect.

The structural, elastic, electronic and magnetic properties of the diluted magnetic semiconductors MnxCa1−xS in the rock-salt phase have been investigated using first-principles calculations with both LDA and LDA + U functional. Features such as lattice constant, bulk modulus, elastic constants, spin-polarized band structure, total and local densities of states have been computed. We predict the values of the exchange constants and the band edge spin splitting of the valence and conduction bands. The hybridization between S-3p and Mn-3d produces small local magnetic moment on the nonmagnetic Ca and S sites. The ferromagnetism is induced due to the exchange splitting of S-3p and Mn-3d hybridized bands. The total magnetic moment per Mn of MnxCa1−xS is 4.4μB and 4.5μB for LDA and LDA + U functional and is independent of the Mn concentration. The unfilled Mn-3d levels reduce the local magnetic moment of Mn from its free space charge value of 5μB–4.4μB and4.5μB for LDA and LDA + U functional due to 3p–3d hybridization.

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MohamedAmine GHEBOULI , Hassina Chouti, Brahim Ghebouli, Nadir Bouarissa, Ercan .Uçgun, Hamza Yasser Ocak, , (2014), Spin-polarized investigation of ferromagnetism on magnetic semiconductors MnxCa1−xS in the rock-salt phase, Materials Chemistry and Physics, Vol:148, Issue:3, pages:1000, Sciencedirect.

We employed the density-functional perturbation theory (DFPT) within the generalized gradient approximation (GGA), the local density approximation (LDA) and the virtual-crystal approximation (VCA) to study the effect of composition on the structure, stability, energy gaps, electron effective mass, the dynamic effective charge, optical and acoustical phonon frequencies and static and high dielectric constants of the rock-salt CaxMg1−xSe and CaxMg1−xTe alloys. The computed equilibrium lattice constant and bulk modulus show an important deviation from the linear concentration. From the Voigt–Reuss–Hill approximation, CaxMg1−xSe and CaxMg1−xTe present lower stiffness and lateral expansion. For Ca content ranging between 0.25 and 0.75, the elastic constants, energy gaps, electron effective mass and dynamic effective charge are predictions. The elastic constants and computed phonon dispersion curves indicate that these alloys are mechanically stable.

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MohamedAmine GHEBOULI , Hassina Choutri, Nadir Bouarissa, Brahim Ghebouli, Messaoud Fatmi, Ercan Uçgun, , (2013), Ab initio calculation of fundamental properties of CaxMg1−xA (A=Se and Te) alloys in the rock-salt structure, Physica E: Low-dimensional Systems and Nanostructures, Vol:49, Issue:, pages:83, Sciencedirect.

We present results of ab initio calculations concerning lattice dynamical and thermal properties of MgS, CaS and their ternary mixed crystals CaxMg1−xS in zinc-blende structure. Results for the phonon modes, dielectric constants, Fröhlich coupling parameter, polaron effective mass, entropy and heat capacities are given for CaxMg1−xS within a composition range 0–1. Generally good agreement is obtained between our results and data available in the literature. Other case, our results are predictions.

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MohamedAmine GHEBOULI , Hassina Choutri, Nadir Bouarissa, , (2013), Lattice dynamics and thermal properties of CaxMg1−xS ternary alloys, Computational Materials Science, Vol:69, Issue:, pages:148, Sciencedirect.

Structural, electronic and optical properties of the ZnSc2S4 and CdSc2S4 cubic spinels have been investigated by means of the full-potential (linearized) augmented plane wave plus local orbitals based on density functional theory. The exchange-correlation potential is treated by the GGA–PBEsol [J.P. Perdew, A. Ruzsinszky, G.I. Csonka, O.A. Vydrov, G.E. Scuseria, L.A. Constantin, X. Zhou, K. Burke, Phys. Rev. Lett. 100 (2008) 136406] and the recently proposed modified Becke–Johnson potential approximation (mBJ) [F. Tran, P. Blaha, Phys. Rev. Lett. 102 (2009) 226401], which successfully corrects the band-gap problem found with GGA for a wide range of materials. The obtained structural parameters are in good agreement with the available experimental data. This gives support for the predict properties for ZnSc2S4 and CdSc2S4. The band structures reveal that both compounds are semiconductor with a direct gap. The obtained gap values show that mBJ is superior for estimating band gap energy. We have calculated the electron and hole effective masses in different directions. The density of states has been analyzed. Based on our electronic structure obtained using the mBJ method we have calculated various optical properties, including the complex dielectric function ɛ(ω), complex index of refraction n(ω), reflectivity coefficient R(ω), absorption coefficient α(ω) and electron energy-loss function L(ω) as functions of the photon energy. We find that the values of zero-frequency limit ɛ1(0) increase with decreasing the energy band gap in agreement with the Penn model. The origin of the peaks and structures in the optical spectra is determined in terms of the calculated energy band structures.

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MohamedAmine GHEBOULI , abdelmadjid bouhemadou, Allali Djamel, Saad Bin-omran, , (2013), Electronic and optical properties of ZnSc2S4 and CdSc2S4 cubic spinels by the modified Becke–Johnson density functional, Solid State Sciences, Vol:20, Issue:, pages:127, Sciencedirect.

We report a detailed study of the compositional dependence of the structural, elastic, electronic and dynamical properties of the quaternary alloys matched to AlP using pseudo-potential plane-wave method based on the density functional theory. The reliability and accuracy of the predicted physical properties mentioned above for are tested by comparing the calculated lattice constant, elastic constants and phonon dispersion curves for the binary AlP with the available experimental and theoretical data in the literature.

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MohamedAmine GHEBOULI , Abdelmadjid Bouhemadou, Brahim Ghebouli, Messaoud Fatmi, Saad Bin-omran, Ercan Uçgun, Hamza Yasser Ocak, , (2013), Structural, elastic, electronic and lattice dynamical properties of III-P quaternary alloys matched to AlP, Materials Science in Semiconductor Processing, Vol:16, Issue:, pages:718, Sciencedirect.

The alkaline platinum hydrides are considered the most promising as hydrogen storage materials. The alloying ability of crystal, elastic constants and related parameters, electronic and optical properties have been studied using pseudo-potential plane–wave method based on the density functional theory. The investigated compounds show a weaker resistance to compression along the principal a-axis and their resistance to shear deformation is lower than the resistance to the unidirectional compression. The band structure indicates that A2PtH6 (A=K, Rb and Cs) are X–X direct gap semiconductors. The effective electron mass at equilibrium has been predicted towards X–Γ, X–W and L–W directions. The strong hybridization between Pt-d and H-s states in the upper valence band translates the existence of covalent bonding character in these compounds. The static optical dielectric constant is inverse proportional to the fundamental gap.

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MohamedAmine GHEBOULI , Salim Bouras, Brahim Ghebouli, Mahfoudh Benkerri, Abdelmadjid Bouhemadou, , (2013), First-principles calculations on elastic, electronic and optical properties for the alkaline platinum hydrides A2PtH6 (A=K, Rb and Cs), Materials Science in Semiconductor Processing, Vol:16, Issue:3, pages:940, Sciencedirect.

The structural, elastic, electronic and optical properties of the gallium monohydrides BaGaXH (X=Si, Ge, Sn) have been investigated by means of first principles calculations. The low values of the B/G ratio of these compounds correspond to the brittle nature, which is due to the hydrogen presence. The bulk modulus, Young's modulus, shear modulus decrease from Si to Sn for BaGaXH (X=Si, Ge, Sn) in the same column in the periodic table. Also the Debye temperature of these compounds has a relative high value indicating that they possess good thermal conductivity. The mean sound velocities have a progressive decrease from silicon (Si) to tin (Sn).

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MohamedAmine GHEBOULI , Tayeb Chihi, Brahim Ghebouli, Abdelmadjid Bouhemadou, Messaoud Fatmi, Saad Bin-omran, , (2013), First-principles calculations of structural, electronic and optical properties of BaGaXH (X=Si, Ge, Sn), Materials Science in Semiconductor Processing, Vol:16, Issue:6, pages:1558, Sciencedirect.

Based on the density functional theory as implemented in the Abinit code under the virtual crystal approximation, the lattice constant, bulk modulus, elastic constants, gap energies, electron effective mass, the dielectric constants and born effective charge in In1−x−yAlxGayAs have been calculated with both GGA and LDA in the range 0≤y≤0.9801. The optical and acoustical phonon frequencies, Fröhlich coupling parameter, deformation energy and polaron effective mass are calculated and their dependence on the Ga content is examined. For AlAs, our results are in reasonable agreement with the known data in the literature; while for other contents our treatments are predictions.

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MohamedAmine GHEBOULI , Hassina CHOUTRI, Nadir Bouarissa, Brahim GHEBOULI, , (2012), First-principles study on stability, energy gaps, optical phonon and related parameters of In1−x−yAlxGayAs alloys, Journal of Solid State Chemistry, Vol:192, Issue:0, pages:161, science direct

M3X (M=Cr, V; X=Si, Ge) compounds are studied using first-principles calculations based on the Density Functional Theory (DFT). It is found that the bulk of Cr3X (X=Si, Ge) compounds are comparable to those of Al2O3, the nearest-neighbor distance DM−M and DM−X in these compounds increase and the bulk modulus decrease, there is a strong interaction between M and M (M=Cr the interaction is stronger). Also the interaction between M (M=Cr, V) and X (X=Ge) is negative, an anti-bonding-type interaction is dominant between these atoms.

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MohamedAmine GHEBOULI , Tayeb Chihi, Messaoud Fatmi, , (2012), Ab initio study of some fundamental properties of the M3X (M=Cr, V; X=Si, Ge) compounds, Physica B: Condensed Matter, Vol:407, Issue:17, pages:3591, Sciencedirect.

The structural, elastic, electronic, optical and thermal properties of the semiconductor perovskite CsPbCl3 were investigated using the pseudo-potential plane wave (PP-PW) scheme in the frame of generalized gradient approximation (GGA) and local density approximation (LDA). The computed lattice constant agrees reasonably with experimental and theoretical ones. The CsPbCl3 crystal behaves as ductile material. The valence bands are separated from the conduction bands by a direct band gap R–R. We distinguished hybridization between Pb-p states and Cl-p states in the valence bonding region. Under compression at P=30 GPa, this material will have a metallic character. The thermal effect on the lattice constant, bulk modulus, Debye temperature and heat capacity CV was predicted using the quasi-harmonic Debye model. To the author's knowledge, most of the studied properties are reported for the first time.

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MohamedAmine GHEBOULI , Brahim GHEBOULI, Messaoud Fatmi, , (2011), First-principles calculations on structural, elastic, electronic, optical and thermal properties of CsPbCl3 perovskite, Physica B: Condensed Matter, Vol:406, Issue:9, pages:1837, science direct

A theoretical study on the structural, elastic, electronic and lattice dynamic properties of AlxYyB1−x−yN quaternary alloys in zinc-blend phase has been carried out with first-principles methods. Information on the lattice parameter, the lattice matching to available substrates and energy band-gaps is a prerequisite for many practical applications. The dependence of the lattice parameter a, bulk modulus B, elastic constants C11, C12 and C44, band-gaps, optical phonon frequencies (ωTO and ωLO), the static and high-frequency dielectric coefficients ε (0) and ε (∞) and the dynamic effective charge Z⁎ were analyzed for y=0, 0.121, 0.241, 0.362 and 0.483. A significant deviation of the bulk modulus from linear concentration dependence was observed. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Young's modulus, Poisson's ratio are numerically estimated in the frame work of the Voigt–Reuss–Hill approximation. The resistance to changes in bond length and lateral expansion in AlxYyB1−x−yN increase with increasing y concentration. We observe that at y concentration about 0.035 and 0.063, AlxYyB1−x−yN changes from brittle to ductile and Γ–X indirect fundamental gap becomes Γ–Γ direct fundamental gap. There is good agreement between our results and the available experimental data for the binary compound AlN, which is a support for those of the quaternary alloys that we report for the first time.

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MohamedAmine GHEBOULI , Brahim GHEBOULI, Messaoud FATMI, , (2011), Theoretical studies of structural, elastic, electronic and lattice dynamic properties of AlxYyB1−x−yN quaternary alloys, Physica B: Condensed Matter, Vol:406, Issue:13, pages:2521, science direct

The structural, elastic, electronic and thermal properties of the MAX phases Ti2SiC and Cr2SiC are studied by means of the pseudo-potential plane wave method within GGA and LDA. The effect of pressure on the normalized lattice constants a/a0 and c/c0 and the internal parameter z is investigated. Our results of elastic constants, sound velocities and Debye temperature are predictions. The Ti2SiC and Cr2SiC compounds behave as ductile material and show a stronger anisotropy. The analysis of the band structure and density of states show that these compounds are electrical conductors, having a strong directional bonding between Ti and C and Cr and C atoms assured by the hybridization of Ti–d and Cr–d atom states with C–p atom states. The thermal effect on the primitive cell volume, bulk modulus, heat capacities CV and CP were predicted using the quasi-harmonic Debye model.

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MohamedAmine GHEBOULI , Brahim GHEBOULI, Messaoud FATMI, Abdelmadjid Bouhemadou, , (2011), Theoretical prediction of the structural, elastic, electronic and thermal properties of the MAX phases X2SiC (X = Ti and Cr), Intermetallics, Vol:19, Issue:12, pages:1936, science direct

Density functional theory pseudo-potential plane-wave calculations are performed in order to predict the structural, elastic and thermodynamic properties of the newly discovered tetragonal intermetallic SrPd2Ge2. The computed equilibrium lattice constants and the internal parameter are in good agreement with the experimental findings. The effect of high pressure, up to 40 GPa, on the lattice constants shows that the contraction along the axis is higher than along the axis. The single-crystal elastic constants and related properties are calculated using the static finite strain technique. We predicted the bulk modulus, shear modulus, Young’s modulus and Poisson’s ratio for ideal polycrystalline SrPd2Ge2 aggregates, using the Voigt–Reuss–Hill approximations. We estimated the Debye temperature and minimum thermal conductivity of SrPd2Ge2 from the average sound velocity. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the temperature and pressure effects on the primitive cell volume, bulk modulus, thermal expansion coefficient, heat capacity and Debye temperature are investigated. This is the first quantitative theoretical prediction of the elastic and thermodynamic properties of the SrPd2Ge2 compound, and it still awaits experimental confirmation.

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MohamedAmine GHEBOULI , Abdelmadjid Bouhemadou, Brahim Ghebouli, Messaoud Fatmi, Saad Bin-omran, , (2011), Prediction study of the elastic and thermodynamic properties of the newly discovered tetragonal SrPd2Ge2 phase, Solid State Communications, Vol:151, Issue:14, pages:976, science direct

A computed investigation on the structural, elastic, electronic, phonon frequencies and thermal properties of AlxScyB1−x−yN quaternary alloys in the zinc-blend phase has been made with first-principles methods. The information on the lattice constant, lattice matching to AlN substrate and energy band gaps is indispensable for various practical applications. We have studied the effect of Sc concentration y (y = 0, 0.152, 0.303, 0.455 and 0.607) on the lattice constant, bulk modulus, elastic constants C11, C12 and C44, band gaps, optical phonon frequencies (ωTO and ωLO), static and high-frequency dielectric coefficient ɛ(0) and ɛ(∞) and dynamic effective charge Z*. We remark an important deviation from the linear concentration dependence of the lattice constant and bulk modulus. The shear moduli, Young's modulus, Poisson's ratio were estimated in the frame work of the Voigt–Reuss–Hill approximation. The resistance to changes in bond length and lateral expansion in AlxScyB1−x−yN increase with increasing y concentration. We observe that at y concentration about 0.11, the Г–X indirect fundamental gap becomes Г–Γ direct fundamental gap in AlxScyB1−x−yN. There is well agreement between our results and the experiment data for AlN binary compound which is a support for those of the quaternary alloys that we report for the first time.

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MohamedAmine GHEBOULI , Brahim GHEBOULI, Messaoud Fatmi, Lebgaa Noudjoud, , (2011), Theoretical investigations of physical properties of AlxScyB1−x−yN quaternary alloys, Materials Chemistry and Physics, Vol:128, Issue:1, pages:195, science direct

Various physical properties of the cubic perovskite-type oxide BiScO3 have been investigated using the pseudo-potential plane-wave (PP-PW) method based on the density functional theory (DFT). The computed equilibrium lattice parameters agree well with the available theoretical data. The elastic constants and their pressure dependence are predicted using the static finite strain technique. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Young’s modulus, Poisson’s ratio, average sound velocity and Debye temperature are numerically estimated in the framework of the Voigt–Reuss–Hill approximation for BiScO3 polycrystalline aggregate. The analysis of the site-projected -decomposed density of states, charge transfer and charge density shows that bonding is predominantly of ionic nature. We distinguish hybridization between Sc-d states and - states in the valence bonding region. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the thermal effect on the lattice constant, bulk modulus, heat capacities and thermal expansion coefficient is calculated.

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MohamedAmine GHEBOULI , Brahim GHEBOULI, Messaoud Fatmi, Bouhemadou Abdelmadjid, , (2011), Calculation of physical properties of the cubic perovskite-type oxide BiScO3 using the PP-PW method based on the DFT theory, Solid State Communications, Vol:151, Issue:12, pages:908, science direct

The structural, electronic, optical and thermodynamic properties of SrxCa1−xO, BaxSr1−xO and BaxCa1−xO ternary alloys in NaCl phase were studied using pseudo-potential plane-wave method within the density functional theory. We modeled the alloys at some selected compositions with ordered structures described in terms of periodically repeated supercells. The dependence of the lattice parameters, band gaps, dielectric constants, refractive indices, Debye temperatures, mixing entropies and heat capacities on the composition x were analyzed for x = 0, 0.25, 0.50, 0.75 and 1. The lattice constant for SrxCa1−xO and BaxSr1−xO exhibits a marginal deviation from the Vegard's law, while the BaxCa1−xO lattice constant exhibits an appreciable upward bowing. A strong deviation of the bulk modulus from linear concentration dependence was observed for the three alloys. The microscopic origins of the gap bowing were detailed and explained. The composition dependence of the dielectric constant and refractive index was studied using different models. The thermodynamic stability of these alloys was investigated by calculating the phase diagram. The thermal effect on some macroscopic properties was investigated using the quasi-harmonic Debye model. There is a good agreement between our results and the available experimental data for the binary compounds which may be a support for the results of the ternary alloys reported here for the first time.

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MohamedAmine GHEBOULI , Brahim GHEBOULI, Abdelmadjid Bouhemadou, Messaoud Fatmi, Khaled Bouamama, , (2011), Structural, electronic, optical and thermodynamic properties of SrxCa1−xO, BaxSr1−xO and BaxCa1−xO alloys, Journal of Alloys and Compounds, Vol:509, Issue:5, pages:1440, science direct

The structural, elastic, electronic, optical and thermal properties of α phase in LiBeN semiconductor have been studied using pseudo-potential plane wave method based on the density functional theory. The computed lattice parameter agrees well with previous theoretical work. The elastic constants and their pressure dependence are predicted using the static finite strain technique. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Young’s modulus, Poisson’s ratio, average sound velocity and Debye temperature are numerically estimated in the frame work of the Voigt–Reuss–Hill approximation for α-LiBeN polycrystalline aggregate. The assignments of the structures in the optical spectra and band structure transitions have been examined and discussed. The thermal effect on heat capacities is investigated by the quasi-harmonic Debye model. To the best of our knowledge, most of the studied properties of the material of interest are reported for the first time.

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MohamedAmine GHEBOULI , Brahim GHEBOULI, Nadir bouarissa, Messaoud FATMI, , (2011), Band parameters of α-LiBeN semiconductor from density functional calculations, Superlattices and Microstructures, Vol:50, Issue:4, pages:319, science direct

The isothermal and non-isothermal ageing of an Al-2.4 wt% Cu alloy have been studied using X-ray diffraction analysis and differential scanning calorimetry (DSC) at different heating rates. Quantitative metallography methods have been applied to measure the corresponding transformed volume fractions at various temperatures and times of precipitation. The variation of the heating rate using DSC technique has allowed us to calculate two kinetics parameters of precipitation which are the Avrami exponent and the activation energy of the process using Kissinger, Ozawa and Bosswell methods. These parameters are similar to those found for the precipitation reaction of θ′ and θ (Al2Cu) phases.

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MohamedAmine GHEBOULI , Messaoud fatmi, Brahim ghebouli, tayeb CHIHI, M. Abdulhafid, , (2011), The kinetics of precipitation in Al-2.4 wt% Cu alloy by Kissinger, Ozawa, Bosswel and Matusita methods, Physica B: Condensed Matter, Vol:406, Issue:11, pages:2277, science direct

Structural, elastic, electronic and thermal properties of the MAX phase Nb2SiC are studied by means of a pseudo-potential plane-wave method based on the density functional theory. The optimized zero pressure geometrical parameters are in good agreement with the available theoretical data. The effect of high pressure, up to 40 GPa, on the lattice constants shows that the contractions along the -axis were higher than those along the -axis. The elastic constants and elastic wave velocities are calculated for monocrystal Nb2SiC. Numerical estimations of the bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, average sound velocity and Debye temperature for ideal polycrystalline Nb2SiC aggregates are performed in the framework of the Voigt–Reuss–Hill approximation. The band structure shows that Nb2SiC is an electrical conductor. The analysis of the atomic site projected densities and the charge density distribution shows that the bonding is of covalent–ionic nature with the presence of metallic character. The density of states at Fermi level is dictated by the niobium d states; Si element has a little effect. Thermal effects on some macroscopic properties of Nb2SiC are predicted using the quasi-harmonic Debye model, in which the lattice vibrations are taken into account. The variations of the primitive cell volume, volume expansion coefficient, bulk modulus, heat capacity and Debye temperature with pressure and temperature in the ranges of 0–40 GPa and 0–2000 K are obtained successfully.

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MohamedAmine GHEBOULI , Brahim GHEBOULI, Abdelmadjid Bouhemadou, Messaoud FATMI, , (2011), Theoretical study of the structural, elastic, electronic and thermal properties of the MAX phase Nb2SiC, Solid State Communications, Vol:151, Issue:5, pages:382, science direct

The structural, elastic, electronic, optical and thermodynamic properties of the cubic perovskite-type hydride KMgH3 have been investigated using pseudo-potential plane-wave method based on the density functional theory. Computed equilibrium lattice constant agrees well with the available experimental and theoretical data. The elastic constants and their pressure dependence are predicted using the static finite strain technique. A linear pressure dependence of the elastic stiffnesses is found. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Young’s modulus, Poisson’s ratio, average sound velocity and Debye temperature are numerically estimated in the frame work of the Voigt–Reuss–Hill approximation for KMgH3 polycrystalline aggregate. The analysis of the site-projected l-decomposed density of states and charge density shows that the bonding is predominantly of ionic nature. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the temperature effect on the lattice constant, bulk modulus, heat capacity and Debye temperature is calculated.

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MohamedAmine GHEBOULI , Brahim GHEBOULI, Bouhemadou Abdelmadjid, Messaoud FATMI, Saad Bin-omran, , (2011), Structural, elastic, electronic, optical and thermodynamic properties of KMgH3, Solid State Sciences, Vol:13, Issue:3, pages:647, science direct

The structural, elastic, electronic and optical properties of XO (X= Ca, Sr and Ba) compounds were investigated by the density functional theory. A good agreement was found between our calculated results and the available theoretical and experimental data of the lattice constants. Young's modulus, Poisson ratio, bulk modulus, elastic constants and their pressure derivatives are also calculated. SrO and BaO compounds present a transition phase at 39.72 and 27.28 GPa. The SrO compound shows a change from direct band gap (Γ–Γ) to indirect band gap (Γ–X) at about 15 GPa. The top of the valence bands reflects the s electronic character for all structures. We investigate the effective mass of electrons as function of pressure at the Γ point for CaO, SrO and BaO compounds. Calculations of the optical spectra have been performed for the energy range 0–60 eV. The origin of the spectral peaks was interpreted based on the electronic structures. The enhancement of pressure increases the static dielectric function and refractive index of CaO, SrO and BaO.

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MohamedAmine GHEBOULI , Brahim Ghebouli, Messaoud Fatmi, Mahfoud Benkarri, , (2010), First-principles calculations of structural, elastic, electronic and optical properties of XO (X=Ca, Sr and Ba) compounds under pressure effect, Materials Science in Semiconductor Processing, Vol:13, Issue:2, pages:92, science direct

Information on the energy band gaps, the lattice parameters and the lattice matching to available substrates is a prerequisite for many practical applications. A pseudopotential plane-wave method as implemented in the ABINIT code is used to the AsxPyN1−x−yAl quaternary alloys lattice matched to AlP substrate to predict their energy band gaps and optical properties. The range of compositions for which the alloy is lattice-matched to AlP is determined. Very good agreement is obtained between the calculated values and the available experimental data. The Debye temperature increase when the bulk modulus is enhanced. We study the variation of elastic constants, the optical phonon frequencies (ωTO and ωLO), the static and high-frequency dielectric coefficient ɛ(0) and ɛ(∞) and the dynamic effective charge Z* with P concentration (y).

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MohamedAmine GHEBOULI , Brahim Ghebouli, Messaoud Fatmi, Tayeb Chihi, Said Boucetta, , (2010), First-principles study of structural, elastic, electronic and lattice dynamic properties of AsxPyN1−x−yAl quaternary alloys, Journal of Alloys and Compounds, Vol:507, Issue:1, pages:120, science direct

The structural, elastic, electronic, optical and thermodynamic properties of the perovskite chloride CsCdCl3 were investigated using the pseudo-potential plane wave (PP-PW) within the Generalized Gradient Approximation (GGA) and Local Density Approximation (LDA). The computed lattice parameter agrees well with experimental and previous theoretical works. Based on the elastic constants and their related parameters, the crystal rigidity and mechanical stability have been discussed. Energy band structure shows that the investigated material is indirect energy band gap semiconductor. The static dielectric constant and static refractive index are indeed, proportional to the fundamental indirect band gap. The thermal effect on the lattice parameter, bulk modulus, volume expansion coefficient, Grüneisen parameter, heat capacities and Debye temperature were predicted using the quasi-harmonic Debye model. To the best of the authors’ knowledge, most of the studied properties are reported for the first time.

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MohamedAmine GHEBOULI , Brahim GHEBOULI, Messaoud Fatmi, Abdelmadjid Bouhemadou, , (2010), First-principles study of the structural, elastic, electronic, optical and thermodynamic properties of the cubic perovskite CsCdCl3 under high pressure, Solid State Communications, Vol:150, Issue:39, pages:1896, science direct

The stability, structural parameters, elastic constants, electronic and optical properties of perovskites CsCaH3 and RbCaH3 were investigated by the density functional theory. The calculated lattice parameters are in agreement with previous calculation and experimental data. The energy band structures, density of states, born-effective-charge and Mulliken charge population were obtained. The perovskites CsCaH3 and RbCaH3 present a direct band gap of 3.15 eV and 3.27 eV at equilibrium. The top of the valence bands reflects the s electronic character for both structures. Furthermore, the absorption spectrum, refractive index, extinction coefficient, reflectivity, energy-loss spectrum, and dielectric function were calculated. The origin of the spectral peaks was interpreted based on the electronic structures. The static dielectric constant and refractive index are indeed, inverse proportional to the direct band gap.

Citation

MohamedAmine GHEBOULI , Brahim GHEBOULI, Messaoud Fatmi, , (2010), First-principles study of structural, elastic, electronic and optical properties of perovskites XCaH3 (X = Cs and Rb) under pressure, Solid State Sciences, Vol:12, Issue:4, pages:587, science direct

Information on the energy band gaps, the lattice parameters and the lattice matching to available substrates is a prerequisite for many practical applications. A pseudopotential plane-wave method as implemented in the ABINIT code is used to the AsxPyN1−x−yB quaternary alloys lattice matched to BP substrate to predict their energy band gaps and lattice dynamic properties. The range of compositions for which the alloy is lattice matched to BP is determined. Very good agreement is obtained between the calculated values and the available experimental data. The compositional dependence of direct and indirect band gaps has been investigated. We study the variation of elastic constants, the optical phonon frequencies (ωTO and ωLO), the high-frequency dielectric coefficient ε(∞) and the born effective charge Z∗ with P concentration.

Citation

MohamedAmine GHEBOULI , Brahim GHEBOULI, Messaoud Fatmi, Said Ibrahim Ahmed, , (2010), First-principles study of structural, elastic, electronic and lattice dynamic properties of AsxPyN1−x−yB quaternary alloys, Computational Materials Science, Vol:48, Issue:1, pages:94, science direct

We present structural, elastic, electronic and optical properties of the perovskites SrMO3 (M=Ti, and Sn) for different pressure. The computational method is based on the pseudo-potential plane wave method (PP-PW). The exchange-correlation energy is described in the generalized gradient approximation (GGA). The calculated equilibrium lattice parameters are in reasonable agreement with the available experimental data. This work shows that the perovskites SrTiO3, and SrSnO3 are mechanically stable and present an indirect band gaps at the Fermi level. Applied pressure does not change the shape of the total valence electronic charge density and most of the electronic charge density is shifted toward O atom. Furthermore, in order to understand the optical properties of SrMO3, the dielectric function, absorption coefficient, optical reflectivity, refractive index, extinction coefficient and electron energy-loss are calculated for radiation up to 80 eV. The enhancement of pressure decreases the dielectric function and refractive indices of SrTiO3 and SrSnO3.

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MohamedAmine GHEBOULI , Brahim GHEBOULI, Tayeb Chihi, Messaoud Fatmi, Said Boucetta, Mounir Reffas, , (2009), First-principles study of structural, elastic, electronic and optical properties of SrMO3 (M=Ti and Sn), Solid State Communications, Vol:149, Issue:47, pages:2244, science direct