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Fouad EL HAJ HASSAN

Professor at the lebanese university

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research activity

In our research, we use the program package WIEN2k which allows us to perform electronic structure calculations of solids using density functional theory (DFT). It is based on the full-potential-linearized augmented plane-wave ((L)APW) + local orbitals (lo) method, one among the most accurate schemes for band structure calculations. In DFT the local (spin) density approximation (LDA) or the improved version of the generalized gradient approximation (GGA) can be used. WIEN2k is an all-electron scheme including relativistic effects and has many features.

Additionally, We use the PWscf (Plane-Wave Self-Consistent Field) which is a set of programs for electronic structure calculations within Density-Functional Theory and Density-Functional Perturbation Theory, using a Plane-Wave basis set and pseudopotentials.

** 2000 - to date: Physics department, Lebanese University. We have studied the structural and electronic properties of bcc Te, Se and SnO2 under high pressure using FP-LAPW method within GGA and EVGGA.

** 2005: 3 months, Senior researcher in the physics department of Isfahan University (IUT) which is an affiliated center of ICTP (Trieste) (Prof. H. Akbarzadeh). We focused our work in the structural, electronic and thermodynamic properties of ZnxMg1-xS, ZnxMg1-xSe and ZnxMg1-xTe semiconductor alloys. In addition the quaternary alloys Zn1-xMgxSeyTe1-y have been investigated using the FP-LAPW method.

** 2004: 3 months, senior researcher in the physics department of Isfahan University (IUT) which is an affiliated center of ICTP. We were worked with the barium chalcogenides (BaX) compounds and boron alloys.

** 2003: 3 months, senior researcher in the physics department of Isfahan University (IUT) which is an affiliated center of ICTP. We were worked in the matlockite cmpounds MFX (M=Ca, Sr, Ba, Pb; X=Cl, Br, I).

** 1997-2000: My PhD thesis deals to study the structural and electronic properties of boron compounds (BN, BP, BAs and BSb) and copper halides (CuCl, CuBr and CuI). To do this, we used the full potential linear augmented plane wave method (FLAPW) and the generalized gradient approximation (GGA) for the exchange-correlation potential. Also, We had study the structural and the disorder effects (bowing) properties of the mixed Cx(BN)1-x, CuClxBr1-x, CuBrxI1-x and CuClxI1-x crystals.

 

Thèmes: Structure de bande, densité de charge, densité d’états, ionicité, pas du réseau, module de rigidité, constante élastique et pression de transition structurale.

Les études ab-initio menées sur l’ensemble des matériaux existants sont nombreuses, et ont donné des résultats fiables en les comparant avec les mesures expérimentales. Parmi ces méthodes ab-initio, la méthode des ondes planes augmentées linéarisées (FP-LAPW) est l’une des plus précises, actuellement, pour le calcul de la structure électronique des solides dans le cadre de la théorie de la fonctionnelle de la densité (DFT). Elle est semblable à la méthode APW avec tous les avantages de la méthode OPW pour traiter les semiconducteurs. Ainsi, la rapidité de calcul de la méthode FP-LAPW est impressionnante par rapport aux autres méthodes de premier principe.

Le sujet de ma thèse à pour but de contribuer à la détermination des propriétés structurales (pas du réseau, module de rigidité et pression de transition) et électroniques (structure de bandes, densité de charges et densité d’états) de matériaux à base de bore et de cuivre à liaisons tétraédriques en utilisant la méthode des ondes planes augmentées linéarisées (FLAPW).

last update: 10/30/2006 11:41:48

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