Density Functional Theory study on the electronic structure and thermoelectric properties of strained Mn4Si7

TL;DR

This study uses Density Functional Theory to investigate how strain affects the electronic structure and thermoelectric properties of Mn4Si7, revealing anisotropic electrical behavior and strain-dependent band gap modifications.

Contribution

It provides new insights into strain effects on Mn4Si7's electronic and thermoelectric properties using DFT and Boltzmann Transport calculations.

Findings

Tensile strain reduces the band gap.

Seebeck coefficient increases with temperature.

Electrical conductivity is highly anisotropic.

Abstract

The strain effect on electronic structure and thermoelectric properties of Higher Manganese Silicides (HMSs) Mn4Si7 was studied using Density Functional Theory (DFT) and through solving Boltzman Transport Equation (BTE). We found that the tensile strain attempts to reduce the band gap while the compressive strain not much affect to band gap. The Seebeck coeficient was found to be increased with increasing temperature, which is very consistent to experiments. The electrical conductivity and power factor show highly degree of anisotropy, where in-plane direction is more dominant. The different behavior of electrical conductivity along in-plane and outof plane direction was explained due to the change of band dispersion in the valence band maximum (VBM).