Thermoelectric transport properties of silicon: Towards an ab initio approach

TL;DR

This paper develops an ab initio method combining the Boltzmann transport equation with density functional theory to accurately predict thermoelectric properties of silicon, considering various scattering mechanisms.

Contribution

It introduces a comprehensive ab initio approach that surpasses relaxation time approximation for calculating thermoelectric coefficients in semiconductors.

Findings

Calculated thermoelectric coefficients agree well with experiments.

Method accounts for multiple scattering mechanisms.

Provides detailed dependence on carrier concentration and temperature.

Abstract

We have combined the Boltzmann transport equation with an {\it ab initio} approach to compute the thermoelectric coefficients of semiconductors. Electron-phonon, ionized impurity, and electron-plasmon scattering rates have been taken into account. The electronic band structure and average intervalley deformation potentials for the electron-phonon coupling are obtained from the density functional theory. The linearized Boltzmann equation has then been solved numerically beyond the relaxation time approximation. Our approach has been applied to crystalline silicon. We present results for the mobility, Seebeck coefficient, and electronic contribution to the thermal conductivity, as a function of the carrier concentration and temperature. The calculated coefficients are in good quantitative agreement with experimental results.