Investigating Anisotropic Raman Modes in 2M-WS₂ via Raman Spectroscopy

The 2M phase WS₂, characterized by a monoclinic structure, has recently been recognized as a topological superconductor candidate, attracting substantial interest. However, a comprehensive study of its anisotropic properties - especially electron-phonon coupling and lattice vibration modes, which are critical for understanding its unconventional superconductivity - remains lacking. In this work, we combine theoretical and experimental approaches to investigate the angle- and polarization-dependent anisotropic Raman-active modes of 2M- WS₂ under different laser excitations. By combining transmission electron microscopy and polarized Raman spectroscopy, we identified the lattice orientation of 2M-WS₂ thin layers. Furthermore, we demonstrate that anisotropic Raman spectroscopy can accurately determine the crystal orientation and twist angle between two stacked 2M-WS₂ layers. Our findings deepen the understanding of the anisotropic properties of 2M-WS₂, paving the way for the application of anisotropic materials in advanced electronic and quantum devices.