Mechanical vibration-induced suppression of transverse acoustic phonons in silicon due to Akhiezer damping

Abstract

Thermoelectric modules that utilize waste heat from machinery are inevitably exposed to mechanical vibrations. Here, we investigated the effects of mechanically induced phonon anharmonicity on Akhiezer damping with three different vibrational modes: Lamé, square extensional, and width extensional modes. We showed complete suppression of the transverse acoustic phonons at 300 K or above for the Lamé mode resonator, which is the reason why the mode has a high quality factor. Our results provide a new fundamental understanding of mechanically induced phonon scattering and rationally enable the design of thermoelectric modules to achieve high performance via mechanical vibrations when they are exposed to mechanical motion. Moreover, this should pave the way for studies of oscillatory motion in short-time-scale vibrational resonators.