Ab initio Green-Kubo Approach for the Thermal Conductivity of Solids

TL;DR

This paper introduces a first-principles Green-Kubo method for accurately calculating the non-radiative thermal conductivity of solid materials using ab initio molecular dynamics, with a novel heat flux definition and convergence scheme.

Contribution

It presents a new ab initio formulation of the Green-Kubo approach with a unique heat flux definition and an extrapolation scheme for efficient convergence.

Findings

Successfully applied to diamond Si and tetragonal ZrO₂.

Achieved accurate size and time convergence.

Demonstrated capability for high and low thermal conductivity materials.

Abstract

We herein present a first-principles formulation of the Green-Kubo method that allows the accurate assessment of the non-radiative thermal conductivity of solid semiconductors and insulators in equilibrium ab initio molecular dynamics calculations. Using the virial for the nuclei, we propose a unique ab initio definition of the heat flux. Accurate size- and time convergence are achieved within moderate computational effort by a robust, asymptotically exact extrapolation scheme. We demonstrate the capabilities of the technique by investigating the thermal conductivity of extreme high and low heat conducting materials, namely diamond Si and tetragonal ZrO$_2$.