Lattice-dynamics of a Disordered solid-solid Interface

TL;DR

This paper investigates how elastic phonons transmit across disordered solid-solid interfaces, revealing frequency-dependent behaviors influenced by disorder correlation length, with implications for understanding thermal transport in disordered materials.

Contribution

It provides a detailed analysis of phonon transmittance at disordered interfaces, highlighting the impact of disorder correlation length and frequency, and introduces simple models to explain these effects.

Findings

Phonon transmittance varies strongly with frequency and disorder correlation length.

At low frequencies, transmittance increases as correlation length decreases.

Power-law behaviors of phonon conductance are identified and match perturbation theory predictions.

Abstract

Generic properties of elastic phonon transport at a disordered interface are studied. The results show that phonon transmittance is a strong function of frequency and the disorder correlation length. At frequencies lower than the van Hove singularity the transmittance at a given frequency increases as the correlation length decreases. At low frequencies, this is reflected by different power-laws for phonon conductance across correlated and uncorrelated disordered interfaces which are in approximate agreement with perturbation theory of an elastic continuum. These results can be understood in terms of simple mosaic and two-colour models of the interface.