Temperature dependence of electronic conductivity from ab initio thermal simulation

TL;DR

This paper introduces the TAHM method, an ab initio simulation-based approach to estimate how electronic conductivity varies with temperature across different materials.

Contribution

The TAHM method extends Hindley-Mott's formula using ab initio molecular dynamics to predict temperature-dependent conductivity in complex systems.

Findings

Reproduces Bloch-Gruneisen behavior in crystalline aluminum.

Captures thermally activated conduction in amorphous and composite materials.

Provides a computationally efficient way to link electronic structure and transport.

Abstract

We present a temperature-dependent extension of the approximate electronic conductivity formula of Hindley and Mott that leverages time-averaged fluctuations of the electronic density of states obtained from ab initio molecular dynamics. By thermally averaging the square of the density of states near the Fermi level, we obtain an estimate of the temperature dependence of the conductivity. This approach termed the thermally-averaged Hindley-Mott (TAHM) method was applied to five representative systems: crystalline aluminum (c-Al), aluminum with a grain boundary (AlGB), a four-layer graphene-aluminum composite (Al-Gr), amorphous silicon (a-Si) and amorphous germanium-antimony-telluride (a-GST). The method reproduces the expected Bloch-Gruneisen decrease in conductivity for c-Al and AlGB. Generally, the reduction (increase) in conductivity for metallic (semiconducting) materials are reproduced. It captures microstructure-induced, thermally activated conduction in multilayer Al-Gr, a-Si and a-GST. Overall, the approach provides a computationally efficient link between time-dependent electronic structure and temperature-dependent transport, offering a simple and approximate tool for exploring electronic conductivity trends in complex and disordered materials.