Deformation potential extraction and computationally efficient mobility calculations in silicon from first principles

TL;DR

This paper introduces a first-principles framework combining DFT and DFPT to accurately extract deformation potentials and compute charge carrier mobility in silicon, aligning well with experimental data and offering computational efficiency.

Contribution

It presents a novel, efficient method for calculating deformation potentials and mobility in silicon from first principles, applicable to complex semiconductors.

Findings

Accurate deformation potentials for silicon obtained from first principles.

Computed electron and hole mobilities show excellent agreement with experiments.

Method is computationally efficient and suitable for complex semiconductors.

Abstract

We present a first-principles framework to extract deformation potentials in Silicon based on density-functional theory (DFT) and density-functional perturbation theory (DFPT). We compute the electronic band structures, phonon dispersion relations, and electron-phonon matrix elements to extract deformation potentials for acoustic and optical phonons for all possible processes. The matrix elements clearly show the separation between intra- and inter-valley scattering in the conduction band, and quantify the strength of the scattering events in the degenerate bands of the valence band. We then use an advanced numerical Boltzmann transport equation (BTE) simulator that couples DFT electronic structures and energy/momentum-dependent scattering rates to compute the transport properties for electrons and holes. By incorporating ionized impurity scattering as well, we calculate the n-type and p-type mobility versus carrier density and make comparisons to experiments, indicating excellent agreement. The fact that the method we present uses well-established theoretical tools and requires the extraction of only a limited number of matrix elements, makes it generally computationally very attractive, especially for semiconductors with a large unit cell and lower symmetry.