Interfacial thermal conductance in graphene/MoS2 heterostructures

Using non-equilibrium molecular dynamics simulations, we investigate the thermal transport in van der Waals heterostructures consisting of alternating multilayer graphene and multilayer MoS2. It is found that the thermal conductance at graphene/MoS2 (G/M) interface is much lower than that at graphene/graphene (G/G) and MoS2/MoS2 (M/M) interfaces. This low interfacial thermal conductance is attributed to the low friction at G/M interface, which significantly reduces the contribution of shearing modes to the thermal conductance. It is also found that there is no thermal rectification at the G/M interface as the thermal conductance is independent on the heat flux direction. Moreover, the interfacial thermal conductance can be effectively tuned by cross-plane strain. More specifically, a 5% tensile strain is able to reduce the interfacial thermal conductance by 70%; while a 5% compressive strain is able to increase the thermal conductance by 150%. Unexpectedly, the G/M interfacial thermal conductance is found to increase with increasing the defect density near the interface, which is in strong contrast to the in-plane thermal conductivity. This unexpected increase in thermal conductance can be explained by the enhanced phonon coupling at the G/M interface arising from the enhanced interface friction caused by the defects.