Temperature-dependent polarized Raman scattering in candidate topological superconductor 2M-WS2

The monoclinic 2M phase of tungsten disulfide (2M-WS₂) has emerged as a promising platform for topological superconductivity, combining topological surface states, anisotropic thermoelectric response, and superconductivity with a critical temperature of ~8.8 K. A detailed understanding of its electron-phonon coupling and phonon anharmonicity is, however, still lacking. Here, we investigate the phonon properties of few-layer 2M-WS₂ as functions of laser power, temperature, polarization, and magnetic field using polarized Raman spectroscopy down to 12.5 K. We uncover an unusual, non-linear temperature dependence of the Raman shifts in selected modes, consistent with strong, mode-dependent electron-phonon interactions that dominate over phonon-phonon scattering at low temperatures. Angle-resolved polarized Raman measurements further reveal a pronounced change in the polarization behavior of the A_g (4) mode at ~316 cm⁻¹ upon cooling, indicating a modification of the underlying lattice and electronic anisotropy. In contrast, the applied magnetic field has a negligible influence on the Raman response over the measured temperature range. Together, these results advance the microscopic understanding of vibrational dynamics and electron-phonon coupling in few-layer 2M-WS₂ and provide important insight into the lattice-electronic interplay relevant for its unconventional superconductivity and potential quantum and thermoelectric device applications.