Two-temperature nonequilibrium molecular dynamics simulation of thermal transport across metal-nonmetal interfaces

We have used a two-temperature nonequilibrium molecular dynamics method for predicting interfacial thermal resistance across metal-nonmetal interfaces. This method is an extension of the conventional nonequilibrium molecular dynamics for the dielectric-dielectric interface, where a temperature bias is imposed and the heat current is derived. We have included the electron degree of freedom for the interfacial thermal transport problem by treating the electron-phonon coupling with the two-temperature model. The method is demonstrated on two model systems, that is, silicon-copper interface and carbon-nanotube-copper interface. Temperature nonequilibrium between electrons and phonons in the metal side is quantitatively predicted, and a temperature drop across the interface is observed. The results agree with experimental data better than those obtained from conventional nonequilibrium molecular dynamics simulations where only phonons are considered. Our approach is capable of taking into account both the electron and lattice degrees of freedom in a single molecular dynamics simulation and is a generally useful tool for modeling interfacial thermal transport across metal-nonmetal interfaces.