Phonon rotoelectric effect

TL;DR

This paper introduces the phonon rotoelectric effect, a new mechanism where electric fields generate phonon angular momentum in certain crystals, expanding understanding of phonon-related phenomena beyond the thermal Edelstein effect.

Contribution

It proposes the phonon rotoelectric effect, linking electric fields to phonon angular momentum in crystals with specific symmetry properties, a novel concept in phonon physics.

Findings

Electric fields can generate phonon angular momentum via lattice distortion.

The effect is analogous to the magnetoelectric effect in symmetry.

Temperature dependence of the effect varies in high- and low-temperature regimes.

Abstract

In crystals with time-reversal symmetry but without inversion symmetry, the phonon angular momentum can be generated by the temperature gradient, and it is called phonon thermal Edelstein effect. On the other hand, when both symmetries are broken and their product is conserved, the phonon angular momentum for any phonon modes at any wave vectors vanishes, and the phonon thermal Edelstein effect does not occur. In this paper, we propose another mechanism of generation of the phonon angular momentum. We show that in such crystals the electric field generates the phonon angular momentum, via the lattice distortion due to the electric field. This effect is in the same symmetry class with the magnetoelectric effect, and we call this effect phonon rotoelectric effect. We discuss the temperature dependence of the phonon angular momentum generated by the temperature gradient and by the electric field in the high- and the low-temperature limits.