A simple nonequilibrium molecular dynamics method for calculating the thermal conductivity

TLDR

The authors present a nonequilibrium molecular dynamics approach to compute thermal conductivity. The method imposes a heat flux on the system and extracts the resulting temperature gradient, and is validated on a Lennard‑Jones fluid. It is simple to implement, works with periodic boundaries, conserves energy and momentum, and samples the rapidly converging temperature gradient rather than the slowly converging heat flux.

Abstract

A nonequilibrium molecular dynamics method for calculating the thermal conductivity is presented. It reverses the usual cause and effect picture. The “effect,” the heat flux, is imposed on the system and the “cause,” the temperature gradient is obtained from the simulation. Besides being very simple to implement, the scheme offers several advantages such as compatibility with periodic boundary conditions, conservation of total energy and total linear momentum, and the sampling of a rapidly converging quantity (temperature gradient) rather than a slowly converging one (heat flux). The scheme is tested on the Lennard-Jones fluid.