Phonon heat transport properties of graphene based on molecular dynamics simulations and lattice dynamics

Abstract

To choose an ideal method to study the phonon properties of graphene, the results of thermal conductivity (TC) of graphene computed using the equilibrium molecular dynamics (EMD), reverse nonequilibrium molecular dynamics (RNEMD) and direct nonequilibrium molecular dynamics (DNEMD) with Tersoff potential are compared, and we find that all of them are very close to each other. While two of them have been compared in the past, there is a lack of comparison of the three methods. Eventually, we choose the Green–Kubo method to study the temperature dependence of TC in graphene and find that the [Formula: see text] diverges with the system temperature T as [Formula: see text]T[Formula: see text] with [Formula: see text] and [Formula: see text] for the direction of armchair and zigzag, respectively, which is in reasonable agreement with the one in recent theoretical and experimental researches. To gain further insight into the TC, the phonon dispersion and the phonon density of states (PDOS), which depend on evaluating the eigenvalues and the eigenvectors of dynamical matrix, are calculated for graphene with dimensions of 30 × 30 unit cell by a combination of EMD simulations and lattice dynamics calculations.