When is the Four-phonon Effect in Half-Heusler Materials more Pronounced?

TL;DR

This study analyzes phonon interactions in Half-Heusler materials, revealing that smaller acoustic phonon bandwidths enhance four-phonon effects, independent of three-phonon scattering suppression.

Contribution

It provides a high-throughput computational analysis linking acoustic phonon bandwidths to four-phonon effects in Half-Heusler materials, challenging previous assumptions about three-phonon suppression.

Findings

Smaller acoustic bandwidths correlate with more pronounced four-phonon interactions.

Three-phonon scattering channels are weakly affected by acoustic-optical gap and bunched features.

The four-phonon effect is more significant in materials with narrower acoustic phonon bandwidths.

Abstract

Suppressed three-phonon scattering processes have been considered to be the direct cause of materials exhibiting significant higher-order four-phonon interactions. However, after calculating the phonon-phonon interactions of 128 Half-Heusler materials by high-throughput, we find that the acoustic phonon bandwidth dominates the three-phonon and four-phonon scattering channels and keeps them roughly in a co-increasing or decreasing behavior. The $aao$ and $aaa$ three-phonon scattering channels in Half-Heusler materials are weakly affected by the acoustic-optical gap and acoustic bunched features respectively only when acoustic phonon bandwidths are close. Finally, we found that Half-Heusler materials with smaller acoustic bandwidths tend to have a more pronounced four-phonon effect, although three-phonon scattering may not be significantly suppressed at this time.