Phonon transmission across an interface between two crystals

TL;DR

This paper introduces a new model for phonon transmission across crystal interfaces that accounts for lattice mismatch, revealing that mismatch causes phonon scattering even without defects and affects transmission coefficients.

Contribution

The paper presents a novel model incorporating lattice mismatch effects into phonon transmission, including an exact solution for quasi one-dimensional cases.

Findings

Lattice mismatch causes phonon scattering at interfaces.

Longitudinal phonons transmit more efficiently than transverse ones at normal incidence.

An exact solution is provided for quasi one-dimensional cases.

Abstract

The new model of phonon transmission across the interface between two crystals is proposed featured by taking into account the mismatch of crystal lattices. It has been found that the mismatch of lattices results in phonon scattering at the interface even in the absence of defects. As it has been shown, at the normal incidence, longitudinally polarized phonons have much larger transmission coefficient than that of transversely polarized phonons, excluding the special resonance cases. For the quasi one-dimensional case the exact solution has been obtained.