Coupled transport of phonons and carriers in semiconductors: A case study of n-doped GaAs

TL;DR

This paper develops a coupled electron-phonon Boltzmann transport equation framework that accurately predicts thermal and electrical transport properties in n-doped GaAs by capturing mutual drag effects, advancing ab initio modeling of semiconductors.

Contribution

The work introduces a novel coupled BTE scheme combining first-principles phonon calculations with electron-phonon models, enabling accurate prediction of transport properties in semiconductors.

Findings

Successfully predicts low-temperature Seebeck coefficient enhancement.

Captures mutual drag effects between electrons and phonons.

Provides insights into charge and heat transport mechanisms.

Abstract

We present a general coupled electron-phonon Boltzmann transport equations (BTEs) scheme designed to capture the mutual drag of the two interacting systems. By combining density functional theory based first principles calculations of anharmonic phonon-phonon interactions with physical models of electron-phonon interactions, we apply our implementation of the coupled BTEs to calculate the thermal conductivity, mobility, Seebeck and Peltier coefficients of n-doped gallium arsenide. The measured low temperature enhancement in the Seebeck coefficient is captured using the solution of the fully coupled electron-phonon BTEs, while the uncoupled electron BTE fails to do so. This work gives insights into the fundamental nature of charge and heat transport in semiconductors and advances predictive ab initio computational approaches. We discuss possible extensions of our work.