Interfacial thermal transport with strong system-bath coupling: A phonon delocalization effect

We study the effect of system-bath coupling strength on quantum thermal transport through the interface of two weakly coupled anharmonic molecular chains using quantum self-consistent phonon approach. The heat current shows a resonant to bi-resonant transition due to the variations in the interfacial coupling and temperature, which is attributed to the delocalization of phonon modes. Delocalization occurs only in the strong system-bath coupling regime and we utilize it to model a thermal rectifier whose ratio can be non-monotonically tuned not only with the intrinsic system parameters but also with the external temperature.