Probing and tuning inelastic phonon conductance across finite-thickness interface

TL;DR

This paper investigates inelastic phonon conductance at material interfaces using molecular dynamics, revealing that transition regions limit thermal boundary conductance and that enhancing phonon scattering can improve heat transfer.

Contribution

It introduces a detailed analysis of inelastic phonon transmission and shows how increasing phonon scattering in transition regions can enhance thermal boundary conductance.

Findings

Inelastic phonon transmission exceeds elastic at the interface.

Transition regions limit the contribution to thermal conductance.

Enhanced phonon scattering increases TBC.

Abstract

Phonon transmission across an interface between dissimilar crystalline solids is calculated using molecular dynamics simulations with interatomic force constants obtained from first principles. The results reveal that although inelastic phonon-transmission right at the geometrical interface can become far greater than the elastic one, its contribution to thermal boundary conductance (TBC) is severely limited by the transition regions, where local phonon states at the interface recover the bulk state over a finite thickness. This suggests TBC can be increased by enhancing phonon equilibration in the transition region for instance by phonon scattering, which is demonstrated by increasing the lattice anharmonicity.