An anomalous wave-like kinetic energy transport in graphene nanoribbons at high heat flux

Most investigations of thermal transport in graphene focused on low heat fluxes when the Fourier heat conduction law is valid. Here thermal transport in armchair graphene nanoribbons was investigated at high heat flux by non-equilibrium molecular dynamics simulations. Besides the energy transported through the Fourier heat conduction, an anomalous wave-like kinetic energy transport was observed. By comparing the two energy transportation paths, we find that the latter constitutes a considerable amount of the total energy and efficiently transports the energy at high heat flux. It means that the heat transfer efficiency in graphene would be greatly improved through wave kinetics. The frequency of the wave (low frequency phonon) would decrease and the amplitude of vibration would increase when the length of the graphene increases. This finding would be useful for thermal analysis when is graphene used as a heat dissipation material.