Influence of the Effective Mass on ab initio Phonon-limited Electron Mobility of GaAs

TL;DR

This study uses ab initio methods to analyze how the electron effective mass influences phonon-limited electron mobility in GaAs, providing insights into the relationship between band structure and transport properties.

Contribution

It introduces a DFT+$U$ based approach combined with Wannier interpolation to systematically study the impact of effective mass variations on electron mobility in GaAs.

Findings

Mobility follows a power-law dependence on effective mass.

Results align well with experimental data.

Method allows efficient temperature-dependent mobility evaluation.

Abstract

We present a comprehensive ab initio study of the influence of band structure corrections, particularly the electron effective mass, on the phonon-limited electron drift and Hall mobilities of GaAs. Our approach is based on the DFT+$U$ method, combined with an iterative solution of the linearized Boltzmann transport equation using the Wannier interpolation technique. We show how this framework allows for accurate refinements of the electronic band structure and phonon dispersion, leading to improved predictions for transport properties. In particular, by varying the Hubbard parameters to purposefully tune the conduction band features, allowing us to reproduce bands with different electron effective mass, we systematically investigate the relationship between mobility and effective mass. In this context, our results show close agreement with semi-empirical relations that follow a power-law dependence. Moreover, this approach can be used to indirectly incorporate temperature effects into the band structure, enabling efficient evaluation of temperature-dependent electron mobilities. Our mobility results exhibit good agreement with experimental data and are comparable to previously reported values obtained using the computationally expensive GW method.