Helicity-resolved Raman scattering of MoS 2 bulk crystal.

Helicity-resolved Raman spectroscopy (HRRS) can effectively distinguish the Raman modes of two-dimensional (2D) layered materials by phonon symmetry. In this paper, we systematically investigated the phonon helicity selection of basal and edge planes of MoS bulk by HRRS. We find that the symmetry of the crystal structure changes the helicity selection of the E, E , and A modes in the edge plane. The theoretical calculation results confirm that the E and A modes of the basal plane exhibit a perfect helicity exchange, and the helicity selections of the E and A modes of the edge plane are eliminated or weakened. Our study provides references for phonon helicity selection of 2D layered materials represented by MoS.