A wave-dominated heat transport mechanism for negative differential thermal resistance in graphene/hexagonal boron nitride heterostructures

Nonlinear thermal transport in graphene/hexagonal boron nitride (h-BN) heterostructure is investigated by the nonequilibrium molecular dynamics method. It is found that negative differential thermal resistance (NDTR) will appear as the applied temperature difference increases. Detailed phonon spectra analysis reveals that the excited out-of-plane acoustic wave plays an important role in the heat transport across such interface. That is, the mechanical wave results in a significant mismatch between the lattice vibrations of graphene and h-BN domains and hinders interfacial thermal transport. In addition, NDTR can be tuned through the temperature parameter. Interestingly, the regime of NDTR becomes smaller and eventually vanishes with increasing the heterostructure length. However, NDTR is insensitive to the variation of system width. The work may be useful for nanoscale thermal managements utilizing the graphene/h-BN heterostructure. Published by AIP Publishing.