Density functional theory study of the electronic structure and the thermoelectric properties of strained Mn4Si7

Abstract

The effect of strain on the electronic structure and the thermoelectric properties of higher manganese silicide (HMS) Mn4Si7 was studied by using density functional theory (DFT) and by solving Boltzmann transport equation (BTE). We found that tensile strain reduced the band gap while compressive strain did not affect the band gap much. The electrical conductivity shows highly anisotropic with the in-plane direction being more dominant while the Seebeck coefficient does not change much, which leads to the the power factor along the in-plane direction being higher compared with that along the out-of-plane direction. The anisotropy of the electrical conductivity was due to a change of the band dispersion in the valence-band maximum (VBM). It was suggested that compressive strain can improve the power factor of Mn4Si7. © 2016, The Korean Physical Society.