Experimental demonstration of optical activity and phonon chirality in orthorhombic van der Waals group-IV monochalcogenides
Year: 2025
Type: article
Abstract: The chiral behavior of phonons has been verified in achiral van der Waals (vdW) layered hexagonal lattices but lacks of experimental evidences in achiral orthorhombic materials like vdW-layered MX (M = Ge, Sn; X = Se, S). Here, we choose SnSe as a model anisotropic MX candidate and explore the optical activity with linearly/circularly polarized Raman spectroscopy along the specified crystal axes by combining with spherical aberration-corrected transmission electron microscopy. Interestingly, besides the robust deflection of linearly polarized photons, we observe the inherent circular-like vibration behavior featuring the chirality of phonon in this orthorhombic lattice, which gives a max degree of circular polarization of ~ 80% by referring to the B3g mode of MX. Our findings not only extend chiral phonons to orthorhombic lattices as theoretically predicted for promising applications in polarized optics, spintronics and phonon filters, but also may provide a strategy for exploring the chiral phonons in anisotropic vdW-layered materials.
Source: Nano Research
Authors: Rui Ge, Yilun Yu, Rong Jin, Shuai Yang, Fengrui Sui, Beituo Liu, Jiawen Dai, Ruijuan Qi, Fangyu Yue
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $5,290
OpenAlex ID: W7083623351