Two-dimensional 2M-WS<sub>2</sub>: a new platform for topological superconductivity?
ORAL · Invited
Abstract
Identifying and verifying topological superconductors remains a central challenge in condensed-matter physics. Recently, the monoclinic 2M phase of tungsten disulfide (2M-WS2) has emerged as a layered, stoichiometric transition-metal dichalcogenide (TMD) that exhibits the highest superconducting transition temperature (≈8.8 K) among TMDs. Combining superconductivity with topological surface states, 2M-WS2 provides a rare single-material platform in which topology and superconductivity naturally coexist. In this talk, I will first describe recent progress in bulk crystal growth of 2M-WS2 and the characterization of its pronounced anisotropy. I will then discuss phase engineering that controllably converts between the 2H and 2M phases. Building on this, I will present transport measurements that reveal a thickness-driven crossover from conventional to unconventional superconductivity, as well as other transport results from 2M-WS2–based junctions. Together, these results establish 2M-WS2 as a promising candidate platform for exploring topological superconductivity and Majorana physics.
*We acknowledge support from the U.S. Department of Energy under Grant No. DE-SC0024188 and the National Science Foundation under Grant No. 2228841.
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Publication:1. Sabin Gautam, et. al. "Anisotropic Raman Scattering and Lattice Orientation Identification of 2M-WS2". Nano Letters 25, 1076 (2025). 2. A K M Manjur Hossain et. al. "Intercalation-Induced Topotactic Phase Transformation of Tungsten Disulfide Crystals". Chemistry of Materials 37, 129 (2025). 3. Piumi I. Samarawickrama et. al. "Crossover from Conventional to Unconventional Superconductivity in 2M-WS2", Nano Letters 24, 16184 (2024). 4. Sabin Gautam et. al. "Controllable superconducting to semiconducting phase transition in topological superconductor 2M-WS2". 2D Materials, 11, 015018 (2024). 5. Piumi I. Samarawickrama et. al. "Two-dimensional 2M-WS2 Nanolayers for Superconductivity", ACS Omega, 6, 2966 (2021).
