Evaluation of diffuse mismatch model for phonon scattering at disordered interfaces

TL;DR

This paper critically evaluates the diffuse mismatch model for phonon scattering at disordered interfaces, revealing its limitations through atomistic simulations and deriving an analytical expression that works well at low frequencies.

Contribution

The study demonstrates that the diffuse mismatch model's assumption of phonon memory loss is invalid at the atomic level and provides an analytical expression for diffuse scattering probability.

Findings

Diffuse phonon scattering does not cause phonons to lose memory of their origin.

The diffuse mismatch model has limited applicability, especially at higher frequencies.

An analytical expression for diffuse scattering probability is effective at low frequencies.

Abstract

Diffuse phonon scattering strongly affects the phonon transport through a disordered interface. The often-used diffuse mismatch model assumes that phonons lose memory of their origin after being scattered by the interface. Using mode-resolved atomic Green's function simulation, we demonstrate that diffuse phonon scattering by a single disordered interface cannot make a phonon lose its memory and thus the applicability of diffusive mismatch model is limited. An analytical expression for diffuse scattering probability based on the continuum approximation is also derived and shown to work reasonably well at low frequencies.