• Theoretical investigation of structural, electronic and thermoelectric properties of $p−n$ type $\rm{Mg_{2}Si_{1−x}Sn_{x}}$ system

• # Fulltext

https://www.ias.ac.in/article/fulltext/pram/094/0006

• # Keywords

Ab-initio calculation; modified Becke and Johnson potential; $\rm{Mg_{2}Si}$; $\rm{Mg_{2}Sn}$; $\rm{Mg_{2}Si_{x}Sn_{1−x}}$ solid solution; thermoelectric materials

• # Abstract

Based on the density functional theory and the Boltzmann transport theory, the thermoelectric properties of $\rm{Mg_{2}Si_{1−x}Sn_{x}}$ solid solution with $x = 0.25, 0.5$ and $075$ were investigated. The calculated structural parameters were in good agreement with the previous work and the mechanical and dynamical stabilities were confirmed. The electronic band structure computed using the Tran-Blaha-modified Becke and Johnson (TB-mBJ) exchange potential indicated that the band gap can be tuned by the alloy effect. We combined first-principles calculations and the semiclassical Boltzmann transport theory by considering the electronic transport in the $\rm{Mg_{2}Si_{1−x}Sn_{x}}$ solid solution to determine the effect of varying the Sn composition on the thermoelectric performance. Our results have shown exceptionally high electrical conductivity for $\rm{Mg_{2}Sn}$ and higher Seebeck coefficient for $\rm{Mg_{2}Si}$. The highest figure of merit (ZT) was predicted for $\rm{Mg_{2}Si_{1−x}Sn_{x}}$ solid solution with x = 0.5 where ZT has reached 0.55 with carrier concentration charge $n = 10^{20} \rm{cm}^{−3}$ (p-type doping) at intermediate temperatures. Consequently, the alloying system with p-type doping may improve the thermoelectric properties compared to the $\rm{Mg_{2}Si}$ and $\rm{Mg_{2}Sn}$ pristine compounds.

• # Author Affiliations

1. Laboratoire d’étude et développement des matériaux semi-conducteurs et diélectriques, Université de Laghouat, Route de Ghardaïa, B.P. 37G, Laghouat, Algeria
2. Laboratoire de physique des matériaux, Université de Laghouat, Route de Ghardaïa, B.P. 73G Laghouat, Algeria
3. Laboratoire des Matériaux et Procédés, Université de Valenciennes et du Hainaut-Cambrésis, Z.I. du Champ de l’Abbesse, 59600 Maubeuge, France

• # Pramana – Journal of Physics

Volume 94, 2020
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019