Anharmonic quantum thermal transport across a van der Waals interface

TL;DR

This paper develops a quantum mechanical theory to analyze anharmonic phonon scattering at interfaces, revealing its significant impact on thermal conductance, especially in weakly coupled heterostructures like graphene and MoS2.

Contribution

It introduces a temperature-dependent Landauer formula for anharmonic phonon scattering and uncovers its dominant role in interfacial thermal transport.

Findings

Anharmonic scattering contribution can dominate harmonic processes at room temperature.

The transmission due to anharmonic scattering can increase unboundedly with temperature in weak coupling.

Anharmonic effects are crucial in understanding thermal transport in heterostructures like graphene/MoS2.

Abstract

We investigate the anharmonic phonon scattering across a weakly interacting interface by developing a quantum mechanics-based theory. We find that the contribution from anharmonic three-phonon scatterings to interfacial thermal conductance can be cast into Landauer formula with transmission function being temperature-dependent. Surprisingly, in the weak coupling limit, the transmission due to anharmonic phonon scattering is unbounded with increasing temperature, which is physically impossible for two-phonon processes. We further reveal that the anharmonic contribution in a real heterogeneous interface (e.g., between graphene and monolayer molybdenum disulfide) can dominate over the harmonic process even at room temperature, highlighting the important role of anharmonicity in weakly interacting heterogeneous systems.