Chiral phonons have been identified in several chiral crystals, primarily in those with trigonal symmetry and threefold screw axes. In this study, chiral phonons in CrSi2, a chiral crystal with a sixfold helical structure, were investigated. Circularly polarized Raman spectroscopy revealed a subtle splitting of doubly degenerate E2 phonon modes between cross-circular polarization configurations. These observations, supported by first-principles phonon calculations, indicate the presence of chiral phonons in CrSi2, expanding the scope of materials that exhibit chiral vibrational modes beyond the conventional trigonal class.
@article{arxiv.2602.17362,
title = {Chiral phonons in sixfold chiral CrSi$_2$: Raman spectroscopy and first-principles calculations},
author = {Gakuto Kusuno and Shingo Kisanuki and Yusuke Kousaka and Yoshihiko Togawa and Takuya Satoh},
journal= {arXiv preprint arXiv:2602.17362},
year = {2026}
}