Pressure enhanced thermoelectric properties in Mg2Sn

TL;DR

This study explores how applying pressure affects the electronic and thermoelectric properties of Mg2Sn, revealing that pressure can significantly enhance its thermoelectric performance in n-type doping.

Contribution

The paper demonstrates that pressure can improve the thermoelectric properties of Mg2Sn, especially in n-type doping, through detailed electronic structure calculations.

Findings

Pressure increases the power factor in n-type Mg2Sn below a critical pressure.

Lattice thermal conductivity remains relatively low near the critical pressure.

Spin-orbit splitting at the Gamma point matches experimental data.

Abstract

Pressure dependence of electronic structures and thermoelectric properties of $\mathrm{Mg_2Sn}$ are investigated by using a modified Becke and Johnson (mBJ) exchange potential, including spin-orbit coupling (SOC). The corresponding value of spin-orbit splitting at $\Gamma$ point is 0.47 eV, which is in good agreement with the experimental value 0.48 eV. With the pressure increasing, the energy band gap first increases, and then decreases. In certain doping range, the power factor for n-type has the same trend with energy band gap, when the pressure increases. Calculated results show that the pressure can lead to significantly enhanced power factor in n-type doping below the critical pressure, and the corresponding lattice thermal conductivity near the critical pressure shows the relatively small value. These results make us believe that thermoelectric properties of $\mathrm{Mg_2Sn}$ can be improved in n-type doping by pressure.