Exactly equivalent thermal conductivity in finite systems from equilibrium and nonequilibrium molecular dynamics simulations

Abstract

In a previous paper (Dong et al., 2021), we showed that the equilibrium molecular dynamics (EMD) method can be used to compute the apparent thermal conductivity of finite systems. It has been shown that the apparent thermal conductivity from EMD for a system with domain length 2 L is equal to that from nonequilibrium molecular dynamics (NEMD) for a system with domain length L . Taking monolayer silicene with an accurate machine learning potential as an example, here we show that the thermal conductivity values from EMD and NEMD agree for the same domain length if the NEMD is applied with periodic boundary conditions in the transport direction. Our results thus establish an exact equivalence between EMD and NEMD for thermal conductivity calculations. • Large-scale MD simulations are performed with an accurate machine learned potential. • Exactly equivalent thermal conductivity in EMD and NEMD has been established. • The exact equivalence is explained in terms of phonon-boundary scattering. • We suggest that EMD serves as a feasible alternative method to NEMD in finite systems.