Thermoelectric properties of topological insulator $\mathrm{BaSn_2}$

San-Dong Guo; Liang Qiu

doi:10.1088/1361-6463/50/1/015101

paper

Thermoelectric properties of topological insulator $BaS n_{2}$

arXiv:1608.05800 · doi:10.1088/1361-6463/50/1/015101

Abstract

Recently, $BaS n_{2}$ is predicted to be a strong topological insulator by the first-principle calculations. It is well known that topological insulator has a close connection to thermoelectric material, such as $B i_{2} T e_{3}$ family. In this work, we investigate thermoelectric properties of $BaS n_{2}$ by the first-principles combined with Boltzmann transport theory. The electronic part is carried out by a modified Becke and Johnson (mBJ) exchange potential, including spin-orbit coupling (SOC), while the phonon part is performed using generalized gradient approximation (GGA). It is found that the electronic transport coefficients between the in-plane and cross-plane directions show the strong anisotropy, while lattice lattice thermal conductivities show an almost isotropy. Calculated results show a very low lattice thermal conductivity for $BaS n_{2}$ , and the corresponding average lattice thermal conductivity at room temperature is 1.69 $W m^{- 1} K^{- 1}$ , which is comparable or lower than those of lead chalcogenides and bismuth-tellurium systems as classic thermoelectric materials. Due to the complicated scattering mechanism, calculating scattering time $τ$ is challenging. By using a empirical $τ$ = $1 0^{- 14}$ s, the n-type figure of merit $Z T$ is greater than 0.40 in wide temperature range. Experimentally, it is possible to attain better thermoelectric performance, or to enhance one by strain or tuning size parameter. This work indicates that $BaS n_{2}$ may be a potential thermoelectric material, which can stimulate further theoretical and experimental works.

7 pages, 7 figures

Thermoelectric properties of topological insulator BaSn2​

Abstract

References in corpus (6)

Thermoelectric properties of topological insulator $BaS n_{2}$