Thermal conductance of graphene and dimerite

Abstract

We investigate the phonon thermal conductance of graphene regarding the graphene sheet as the large-width limit of graphene strips in the ballistic limit. We find that the thermal conductance depends weakly on the direction angle θ of the thermal flux periodically with period π/3. It is further shown that the nature of this directional dependence is the directional dependence of group velocities of the phonon modes in the graphene, originating from the D6h symmetry in the honeycomb structure. By breaking the D6h symmetry in graphene, we see more obvious anisotropic effect in the thermal conductance as demonstrated by dimerite. © 2009 The American Physical Society.