SAMIA Ben yettou

Khaiat Mouhamed

Etude de premiers principes des propriétés structurales, élastiques et thermodynamiques de pérovskite SrTiO3 de type-cubique

BOUDJELLAL Achwaq

Etude de premier principe de quelques propriétés physiques de GaN dans la phase zinc blende

MEZAACHE Fatiha

Calcul de premier principe de quelques propriétés physiques de composé binaire CdSe dans la phase zinc blende

DILMI Wafa

Etude de premier principe des propriétés structurales électroniques et élastiques de CdTe dans la phase zinc blende

BALBOUL Fatna , KABACHE Sabah, LAKHDARI Mounira

طرق وتلبيد الخزفيات

SAAIDI Sabiha , ROUBACHE Sabah

Etude les caractéristiques de frittage des matériaux réfractaire préparer à base (Al2O3, SiO2)

A comprehensive first-principles investigation has been conducted on the α-phase LiGaSi1−xCx alloyto explore its structural, mechanical, electronic, thermodynamic, and lattice dynamical properties.The study employs density functional theory (DFT) within the plane-wave pseudopotential method,using the alchemical mixing approximation as implemented in the ABINIT code. Ground-stateproperties, including lattice constants, bulk modulus, elastic constants (Cij), Young’s modulus (E),shear modulus (G), and energy gaps, were calculated for the parent compounds LiGaSi and LiGaC,showing strong agreement with previously reported theoretical results. For the LiGaSi1−xCx alloy,these properties are reported here for the first time, providing new insights into its compositionaldependence and mechanical stability. Electronic structure analysis, performed using the Tran–Blahamodified Becke–Johnson (TB-mBJ) exchange–correlation potential, reveals that the alloy exhibits anindirect bandgap (Γ to X) across all compositions, with the bandgap tunable from 0.59 eV to 1.51 eVdepending on the carbon content. This tunability suggests promising potential for optoelectronicapplications such as photosensors and light-emitting diodes (LEDs). Thermodynamic properties,including unit cell volume, bulk modulus, thermal expansion coefficient, heat capacity, and entropy,were examined as functions of temperature and carbon concentration. Phonon dispersion relationsand phonon frequency analyses confirm the dynamical stability of the α-phase LiGaSi1−xCx alloyacross the full compositional range studied.

Citation

NADIR Bouarissa , SALIMA Saib , Samia BEN YETTOU , Bachiri Zeyneb, , (2025-08-26), Computational investigation of structural, mechanical, electronic, thermodynamic, and lattice dynamical properties of α-phase LiGaSi1-xCx alloys for advanced energy applications, Physica Scripta, Vol:100, Issue:, pages:085998, IOP Science

Wide band gap II-VI compound semiconductors are expected to be one of the most vital materials for high performance optoelectronic devices such as light-emitting diodes and laser diodes operating in the blue or ultraviolet spectral region. Besides, the high ionicity of these compounds makes them good candidates for high electro-optical and electromechanical coupling. The objective of this thesis is to study the structural, electronic, elastic, piezoelectric and dynamic of the CdSexTe1-x alloy properties in both zinc blend and wurtzite phases with ab-initio methods. Our calculations are based on the method of the pseudo-potentials and plane waves, Our study is based on functional theory (DFT) in the local density approximation (LDA) under the virtual Crystal approximation (VCA) and the density functional perturbation theory (DFPT). On the one hand, our results are in agreement with the available experimental results and theoretical, and on the other hand are a reliable prediction. Key words: structural properties, electronic properties, elastic properties, dynamic properties, II - VI semiconductor, ternary alloys, CdSexTe1-x.

Citation

SamiaBEN YETTOU , ,(2016); Calcul de premier principe de quelques propriétés physiques de quelques alliages semi-conducteurs,Université Mohamed Khider de Biskra,

Le but de ce cours est de donner les bases essentielles de la structure de la matière comme préparation au cours de physique de l'état solide (maille, nœud , Réseau cristallin, structure cristalline, système cristallin, les indices d’une direction ou d’un plan cristallographique, diffraction des rayons X dans un solide, propriétés thermiques et électriques des solides, bandes d’énergie dans un semi-conducteur).

Citation

SamiaBEN YETTOU , ,(2016); Physique du Solide,Université Mohamed Boudiaf de M'sila,

Ab initio calculations in the framework of plane-wave pseudopotential implementation of the density functional theory with the local density approximation and response-function calculations have been performed so as to investigate elastic, lattice dynamical and thermal properties of zinc-blende CdSexTe1−x ternary alloys. The composition dependence of the elastic constants and phonon frequencies has been studied. In addition, the influence of temperature on the entropy and heat capacity is also examined and discussed. The results presented in the present contribution show good agreement with the data available in the literature and yield a general understanding of the fundamental properties of CdSexTe1−x ternary alloys.

Citation

Samia BEN YETTOU , , (2015), Elastic, lattice dynamical and thermal properties of zinc-blende CdSexTe1−x ternary alloys, Chemical Physics, Vol:457, Issue:18, pages:147-151, Elsevier BV

We performed density functional theory studies of the structural, elastic and piezoelectric properties of CdSexTe1−x in the wurtzite structure. The compositional dependence of such properties of interest over the whole composition range was analyzed and discussed using an ab initio pseudopotential approach under the virtual crystal approximation within both the local density approximation (LDA) and the generalized gradient approximation (GGA). For parent compounds, i.e. CdTe and CdSe, our findings agree well with the available data in the literature. Our results for piezoelectric properties for the alloy under load in the wurtzite structure are reported for the first time and may serve as a reference for future studies. It is found that the employment of the GGA instead of the LDA has an effect on the structural, elastic and piezoelectric parameters of the material of interest.

Citation

Samia BEN YETTOU , , (2015), First principles study of structural, elastic and piezoelectric properties of CdSexTe1−x ternary alloys in the wurtzite structure, Physica Scripta, Vol:90, Issue:, pages:7, JOP