| Titre : | Structures et propriétés électroniques et thermoélectriques des composés de type Mg2X (X=Si, Ge, Sn) : Etude comparative |
| Auteurs : | NEGADI Abdelhakim, Auteur ; DINE Khaled, Directeur de thèse |
| Type de document : | texte manuscrit |
| Editeur : | Université de Saida Dr MOULAY Tahar Faculté des Sciences Département de Physique, 2020/2021 |
| Format : | 81ص |
| Accompagnement : | CD |
| Langues: | Français |
| Index. décimale : | BUC-M 008067 |
| Catégories : |
MASTER Spécialité : PHYSIQUE Option : physique computationnelle |
| Mots-clés: | : Semiconductor: Mg2X (X = Si: Ge and Sn):DFT, GGA, TB-mBJ, thermoelectric. |
| Résumé : |
Abstract :
In this work, an ab initio study is carried out, within the framework of the density functional theory (DFT), to revisit the structural, electronic and thermoelectric properties of three semiconductor compounds (Mg2Si, Mg2Ge and Mg2Sn), and this by using the approximation of the generalized gradient (GGA-PBE). For a better semi-local treatment of the exchange and correlation potential, the method of Tran-Blaha modified Becke-Johnson (TB-mBJ) was used. The structural parameters obtained (lattice parameters, volumes, bulk modulus, etc.) are in very good agreement with the results of other theoretical and experimental work. The study of the electronic band structure and the density of states of these semiconductor compounds shows that the three Mg2X compounds (X = Si, Ge and Sn) have an indirect gap in the X direction, and that the TB-mBJ correction has much improved the value of the gap and provides a better description of the electronic properties of these compounds. The calculation of thermoelectric coefficients and parameters is performed using the BotzTraP code, which uses the transport equation based on the semi-classical Boltzmann model. The latter confirmed that these three semiconductor compounds have a very good figure of merit, and a high power factor and Seebeck coefficient, and are therefore very interesting and very promising from a thermoelectric point of view. |
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Documents numériques (1)
BUC-M 008067 Adobe Acrobat PDF |
