Abstract-Breakdown of Herring’s processes in cubic semiconductors for subterahertz longitudinal acoustic phonons

Maxime Markov, Jelena Sjakste, Nathalie Vast, Romain Legrand, Bernard Perrin, Lorenzo Paulatto,

https://journals.aps.org/prb/accepted/46075O66Ife1e83c71e16b1359e63bafffb93120b

In the present work we explain the anomalous behavior of the attenuation of the longitudinal acoustic phonon in GaAs as a function of the phonon energy $\omega$ in the sub-THz domain. These attenuations along the [100] direction show a plateau between 0.6 and 1~GHz at low temperatures. We found an excellent agreement between measurements performed by some of us, and new {ab initio} calculations of third-order anharmonic processes. The formation of the plateau is explained by the competition between different phonon-phonon scattering processes as Herring’s mechanism, which dominates at low frequencies, saturates and disappears. The plateau is shown to be determined by the phononic final-state phase-space available at a given temperature. We predict that a change of scattering mechanism should also show up in the attenuation of silicon around 1.2-1.7~THz, and argue that the attenuation plateau is a general feature of cubic semiconductors.