Impact of the acoustic phonon bandwidth on three-phonon and four-phonon scattering in half-Heusler materials

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. Our study gives insights into the high-order four-phonon effect in solids, which has guiding significance for designing thermal management materials.