Molecular Dynamics Prediction of Thermal Conductivity of GaN Films and Wires at Realistic Length Scales

TL;DR

This paper develops a scaling law-based method to accurately predict the thermal conductivity of GaN nanostructures at realistic sizes using molecular dynamics simulations, overcoming size limitations of traditional methods.

Contribution

It introduces a novel scaling approach that enables reliable extrapolation of thermal conductivity for nanostructures from molecular dynamics data.

Findings

Scaling law accurately predicts thermal conductivity across sizes.

Method successfully applied to GaN nanostructures.

Predictions match experimental and theoretical expectations.

Abstract

Recent molecular dynamics simulation methods have enabled thermal conductivity of bulk materials to be estimated. In these simulations, periodic boundary conditions are used to extend the system dimensions to the thermodynamic limit. Such a strategy cannot be used for nanostructures with finite dimensions which are typically much larger than it is possible to simulate directly. To bridge the length scales between the simulated and the actual nanostructures, we perform large-scale molecular dynamics calculations of thermal conductivities at different system dimensions to examine a recently developed conductivity vs. dimension scaling theory for both film and wire configurations. We demonstrate that by an appropriate application of the scaling law, reliable interpolations can be used to accurately predict thermal conductivity of films and wires as a function of film thickness or wire radius at realistic length scales from molecular dynamics simulations. We apply this method to predict thermal conductivities for GaN wurtzite nanostructures.