Étude des propriétés physiques du BaFZnP de type LaOAgS via des méthodes ab initio / Bilal Tahir  

Public ISBD Titre : Étude des propriétés physiques du BaFZnP de type LaOAgS via des méthodes ab initio Type de document : document électronique Auteurs : Bilal Tahir ; Nacir Guechi, Directeur de thèse Editeur : Setif:UFA Année de publication : 2024 Importance : 1 vol. (110 f.) Catégories : Thèses & Mémoires:Physique Mots-clés : BaFZnP  ab initio calculations  DFT  GGA  TB-mBJ  Structural parameters  Elastic Constants  Electronic structure  Optical functions  Thermoelectric coefficients Résumé : We conducted ab-initio calculations on the structural, elastic, electronic, optical, and thermoelectric properties of the BaFZnP compound, which crystallizes in a LaOAgS-type structure, using the software packages CASTEP and Wien2K. The calculations were executed employing the pseudopotential plane-wave (PP-PW) and full-potential linearized augmented plane wave (FP-LAPW) methods within the density functional theory (DFT) framework. The exchange-correlation effects were modeled via the PBEsol version of the generalized gradient approximation (GGA-PBEsol) and the Tran-Blaha modified Beck-Johnson (TB-mBJ) potential. The calculated equilibrium lattice parameters are in exellent agreement with the available experimental data. The monocrystalline and polycrystalline elastic moduli of the title compound were determined via the stress-strain method. The calculated band structure shows a direct band gap of    type. The partial densities of electronic states were calculated to determine the nature of the chemical bonds. We examined spectra of various optical functions, including the dielectric function, refractive index, absorption coefficient, and reflectivity coefficient across an energy range from 0 to 12 eV. The microscopic origin of the electronic states responsible for the structures of the optical spectra is determined. The FP-LAPW band structure and the semi-classical Boltzmann transport theory were used to study the chargecarrier concentration and temperature dependences of the thermoelectric parameters, including Seebeck coefficient, electrical conductivity, thermal conductivity and figure of merit. Our findings indicate that the thermoelectric parameters of BaFZnP in the p-type doping exhibit larger values compared to those in the n-type doping. In order to facilitate and guide the experimental work we have calculated the optimal p-type doping concentration and temperature that yield the maximum values of the figure of merit of the title compound Côte titre : DPH/0306 En ligne : http://dspace.univ-setif.dz:8888/jspui/bitstream/123456789/4659/1/%c3%89tude%20d [...] Étude des propriétés physiques du BaFZnP de type LaOAgS via des méthodes ab initio [document électronique] / Bilal Tahir ; Nacir Guechi, Directeur de thèse . - [S.l.] : Setif:UFA, 2024 . - 1 vol. (110 f.). Catégories : Thèses & Mémoires:Physique Mots-clés : BaFZnP  ab initio calculations  DFT  GGA  TB-mBJ  Structural parameters  Elastic Constants  Electronic structure  Optical functions  Thermoelectric coefficients Résumé : We conducted ab-initio calculations on the structural, elastic, electronic, optical, and thermoelectric properties of the BaFZnP compound, which crystallizes in a LaOAgS-type structure, using the software packages CASTEP and Wien2K. The calculations were executed employing the pseudopotential plane-wave (PP-PW) and full-potential linearized augmented plane wave (FP-LAPW) methods within the density functional theory (DFT) framework. The exchange-correlation effects were modeled via the PBEsol version of the generalized gradient approximation (GGA-PBEsol) and the Tran-Blaha modified Beck-Johnson (TB-mBJ) potential. The calculated equilibrium lattice parameters are in exellent agreement with the available experimental data. The monocrystalline and polycrystalline elastic moduli of the title compound were determined via the stress-strain method. The calculated band structure shows a direct band gap of    type. The partial densities of electronic states were calculated to determine the nature of the chemical bonds. We examined spectra of various optical functions, including the dielectric function, refractive index, absorption coefficient, and reflectivity coefficient across an energy range from 0 to 12 eV. The microscopic origin of the electronic states responsible for the structures of the optical spectra is determined. The FP-LAPW band structure and the semi-classical Boltzmann transport theory were used to study the chargecarrier concentration and temperature dependences of the thermoelectric parameters, including Seebeck coefficient, electrical conductivity, thermal conductivity and figure of merit. Our findings indicate that the thermoelectric parameters of BaFZnP in the p-type doping exhibit larger values compared to those in the n-type doping. In order to facilitate and guide the experimental work we have calculated the optimal p-type doping concentration and temperature that yield the maximum values of the figure of merit of the title compound Côte titre : DPH/0306 En ligne : http://dspace.univ-setif.dz:8888/jspui/bitstream/123456789/4659/1/%c3%89tude%20d [...]

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DPH/0306	DPH/0306	Thèse	Bibliothéque des sciences	Français	Disponible Disponible

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