Chiral phonons throughout reciprocal space

The properties of chiral phonons (phonons with associated angular momentum and associated magnetic moments) have been studied mainly at the Γ point (where they can be created by circularly polarized excitations) and other high-symmetry points in the Brillouin zone. However, they can arise at arbitrary wavevectors in materials which lack a centre of symmetry. Thereby, phonon chirality can affect the bulk properties of solids, especially in cases where time reversal symmetry is broken, leading to, for example, the phonon thermal Hall effect. We have selected noncentrosymmetric materials in which chiral phononic effects are enhanced by structural and chemical factors, and calculated the distribution of chiral phonons throughout the Brillouin zone and their properties in order to predict chiral phononic responses to external perturbations (e.g. electromagnetic and thermal stimuli).