A new approach for electronic heat conduction in molecular dynamics simulations

TL;DR

This paper introduces a novel two-temperature molecular dynamics approach that models electronic and phonon heat conduction without auxiliary meshes, enabling detailed simulations of energy transfer in nanoscale systems.

Contribution

The new method employs a master equation for electronic heat conduction, simplifying coupling with MD codes and improving simulation of electron-phonon interactions.

Findings

Validated through multiple examples in LAMMPS

Effectively models energy transfer in complex geometries

Demonstrates applicability to irradiation and laser-material interactions

Abstract

We present a new approach for the two-temperature molecular dynamics (MD) model for coupled simulations of electronic and phonon heat conduction in nanoscale systems. The proposed method uses a master equation to perform heat conduction of the electronic temperature eschewing the need to use a basis set to evaluate operators. This characteristic allows us to seamlessly couple the electronic heat conduction model with molecular dynamics codes without the need to introduce an auxiliary mesh. We implemented the methodology in the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code and through multiple examples, we validated the methodology. We then study the effect of electron-phonon interaction in high energy irradiation simulations and the effect of laser pulse on metallic materials. We show that the model provides an atomic level description in complex geometries of energy transfer between phonons and electrons. Thus, the proposed approach provides an alternative way to the two-temperature molecular dynamics models. The parallel performance and some aspects of the implementation are presented.