Nonlinearity enhanced interfacial thermal conductance and rectification

TL;DR

This paper introduces a quantum self-consistent mean field theory to analyze nonlinear interfacial thermal transport, revealing how nonlinearity can enhance heat transfer and induce rectification at atomic junctions.

Contribution

The paper develops a precise QSCMF theory for nonlinear interfacial thermal transport, providing new insights into phonon transport channels and rectification mechanisms.

Findings

Nonlinearity can enhance phonon-mediated heat transfer at interfaces.

Thermal conductance exhibits nonmonotonic behavior with increasing nonlinearity or temperature.

Interfacial nonlinearity induces thermal rectification dependent on lead mismatch and coupling.

Abstract

We study the nonlinear interfacial thermal transport across atomic junctions by the quantum self-consistent mean field (QSCMF) theory based on nonequilibrium Green's function approach; the QSCMF theory we propose is very precise and matches well with the exact results from quantum master equations. The nonlinearity at the interface is studied by effective temperature dependent interfacial coupling calculated from the QSCMF theory. We find that nonlinearity can provide an extra channel for phonon transport in addition to the phonon scattering which usually blocks heat transfer. For weak linearly coupled interface, the nonlinearity can enhance the interfacial thermal transport; with increasing nonlinearity or temperature, the thermal conductance shows nonmonotonical behavior. The interfacial nonlinearity also induces thermal rectification, which depends on the mismatch of the two leads and also the interfacial linear coupling.