Exposing the hidden influence of selection rules on phonon-phonon scattering by pressure and temperature tuning

TL;DR

This study uses ab initio calculations to reveal how selection rules influence phonon scattering, showing pressure and temperature effects on thermal conductivity that are observable in experiments, with implications for materials like boron phosphide and silicon carbide.

Contribution

It uncovers the hidden role of selection rules in phonon scattering through pressure and temperature dependence, providing new insights into thermal conductivity behavior in certain compounds.

Findings

Boron phosphide shows a sharp increase in thermal conductivity with pressure.

Thermal conductivity peaks and then decreases at high pressure.

Similar anomalous behavior predicted for silicon carbide.

Abstract

Using ab initio calculations, we show that the hidden influence of selection rules on three-phonon scattering can be exposed through anomalous signatures in the pressure ($P$) and temperature ($T$) dependence of the thermal conductivities, $\kappa$, of certain compounds. Boron phosphide reveals such underlying behavior through an exceptionally sharp initial rise in $\kappa$ with increasing $P$, which may be the steepest of any material, and also a peak and decrease in $\kappa$ at high $P$. These features are in stark contrast to the measured behavior for many solids, and occur at experimentally accessible conditions. Similar anomalous behavior is predicted for silicon carbide and other related materials.