Raman Tensor of van der Waals MoSe 2

Molybdenum selenide (MoSe ) is a van der Waals layered crystal with both the anisotropic light absorption and light scattering outside its surface. At present, the study of the Raman tensor of MoSe , which affects and even determines the inelastic light scattering's anisotropy, is not sufficient. In this research, with the aim of studying the out-of-plane anisotropy, we performed systematic angle-resolved polarized Raman (APR) spectroscopy and abstracted complete Raman tensors both experimentally and theoretically. In addition, according to first-principles calculations, in different conditions of laser excitation, MoSe has various Raman tensor forms, of which the phase difference between Raman tensor elements of the mode is a particular one. By studying the anisotropic optical absorption properties, we confirmed that it is the dispersion and absorption of MoSe under different pump light that lead to the photon-energy-dependent phase differences.