SPICE Workshop on Chiral Phonons, July 29th - 31st 2025
Jun-Ichiro Kishine
We present a microscopic formulation of chiral phonons propagating along the helical axis in chiral crystals by explicitly deriving their wavefunctions and analyzing their electron-phonon interactions. Our study reveals that the interaction vertex reflects the conservation not only of crystal momentum (CM) but also of crystal angular momentum (CAM), thereby highlighting a key symmetry property unique to chiral helical systems. This framework enables a detailed understanding of physical processes involving chiral phonons. In addition, we construct a phononic analogue of Zilch—a known optical measure of chirality—and discuss its connection to phonon angular momentum.
Refs.
[1] T. Tateishi, A. Kato and J. Kishine, to appear in J. Phys. Soc. Jpn., arXiv:2503.13855
[2] J. Kishine, A.S. Ovchinnikov, and A. Tereshchenko, PRL125,245302 (2020)
[3] A. Kato and J. Kishine, J.Phys.Soc.Jpn.92, 075002 (2023)
[4] K. Ishito et al., Nature Phys. 19, 35-39 (2023)