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

TL;DR

This paper investigates how strong system-bath coupling influences quantum thermal transport at interfaces, revealing phonon delocalization effects that enable tunable thermal rectification.

Contribution

It introduces a quantum self-consistent phonon approach to analyze phonon delocalization due to strong coupling, leading to novel thermal rectifier designs.

Findings

Heat current transitions from resonant to bi-resonant with coupling changes.

Phonon delocalization occurs only in strong coupling regimes.

Thermal rectification ratio can be externally tuned.

Abstract

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.