Probing the properties of lattice vibrations and surface electronic states in magnetic semiconductor CrPS4

Searching for multifunctional materials with magnetism and semiconductivity is one of the goals of research into two-dimensional (2D) systems. Herein, we report a chemical vapor transport method to successfully synthesize a layered magnetic semiconductor, CrPS4. Under parallel and perpendicular polarization configurations, the anisotropic optical response of the (001) surface was investigated by polarized Raman spectroscopy; the Raman peak intensity was recorded with the crystal rotated from 0 degrees to 360 degrees, taking the symmetry of the Raman tensor into account; the A or B vibrational mode of different Raman peaks can be clearly distinguished. Moreover, the electronic state of the (001) single-crystal surface was investigated by ultraviolet photoelectron spectroscopy (UPS), which reveals the valence band position and work function of the (001) surface.