Effects of high order interatomic potential on elastic phonon scatterings

TL;DR

This paper explores how high-order interatomic potentials influence elastic phonon scattering, revealing their significant role in phonon transport and the formation of localized phonons, especially at elevated temperatures.

Contribution

It demonstrates that considering only quadratic potentials is insufficient, highlighting the importance of high-order potentials in elastic phonon scattering and transport.

Findings

High-order potentials cause multiple-phonon scattering.

High-order potentials significantly impact elastic phonon scattering.

Localized phonons form due to high-order potentials, especially at higher temperatures.

Abstract

Interatomic potentials beyond quadratic order provide scattering sources for phonon transport in lattice. By using a weakly-interacting interface model, we investigated the relation between the order of interatomic potential and the multiple-phonon scattering process. We find that high order interatomic potential not only causes multiple-phonon scattering processes, but also has significant impacts on elastic phonon scattering processes. Using fourth order potential as an example, we show that it can significantly affects elastic phonon scatterings, through the formation of localized phonons. Such impact is closely related to the correlations of interfacial atoms and it becomes more significant with increasing temperature. Our work suggests that it is insufficient to consider only quadratic potential to investigate elastic phonon transport.