A material’s vibrations can now be controlled with an electric field

For the first time, researchers have directly observed and reversibly switched the chirality of atomic vibrations—specifically phonon angular momentum—within the ferroelectric material barium titanate (BaTiO3). Employing circularly dichroic resonant inelastic X-ray scattering, the team directly resolved phonon chirality through angular momentum transfer between X-rays and the crystal lattice. This work establishes a "robust and non-volatile gyroelectric effect," offering a pathway to manipulate vibrational states even after power is removed and paving the way for potential advances in phonon-based technologies. The results demonstrate phonon angular momentum as an electrically controllable degree of freedom. The technologically relevant ferroelectric barium titanate, or BaTiO3, now exhibits reversible switching of phonon…