Electric field switching of chiral phonons

TL;DR

This paper demonstrates the electric-field control of chiral phonons in BaTiO3 using CD-RIXS, revealing a reversible gyroelectric effect and opening avenues for phonon-based information technologies.

Contribution

It introduces a method for deterministic, non-volatile switching of phonon angular momentum via electric fields in a ferroelectric material.

Findings

Reversible gyroelectric effect observed for chiral phonons.

Excellent agreement between experimental dichroism and first-principles predictions.

Stable control of phonon chirality for at least 15 hours.

Abstract

Lattice vibrations carrying angular momentum, known as chiral phonons, have emerged as a promising route to control and understand complex material properties, yet their deterministic manipulation remains largely unexplored. Here we demonstrate electric-field switching of phonon angular momentum in the technologically relevant ferroelectric BaTiO3. Using circularly dichroic resonant inelastic X-ray scattering (CD-RIXS) at the oxygen K edge, we directly probe the phonon angular momentum and compare the measured dichroism with first-principles predictions of phonon-mode chirality. We find excellent agreement, revealing a momentum-dependent circular-dichroism contrast that exhibits a reversible gyroelectric effect, stable for at least 15 hours. Our results establish a robust mechanism for non-volatile control of chiral phonons and point towards new opportunities for phonon-based information and energy technologies.