Temperature-dependent polarized Raman modes of 2M-WS₂

The 2M phase tungsten disulfide (2M-WS₂) has recently emerged as a candidate topological superconductor, featuring topological surface states, anisotropic thermoelectricity, and superconductivity with 𝑇c ~ 8.8 T. Temperature-dependent Raman spectroscopy offers a sensitive probe of phonon anharmonicity and electron–phonon interactions. In this talk, we present polarized, temperature-dependent Raman measurements on few-layer 2M-WS₂ from 12.5 to 295 K. The 𝐴_𝑔 and 𝐵_𝑔 phonon modes exhibit pronounced, nonlinear temperature-dependent frequency shifts, especially at low temperatures. Angle-resolved polarization measurements in a parallel configuration reveal a distinct change in the polarization response of the 𝐴_𝑔 mode near 316 cm^-1 upon cooling to 12.5 K. Furthermore, the phonon linewidths evolve nonmonotonically with temperature, consistent with strong electron-phonon coupling that dominates over phonon–phonon scattering. These results may provide new insights into the origin of the unconventional superconductivity in few-layer 2M-WS₂.