Superconductivity in twisted bilayer WSe$_2

• Main Authors: Guo, Yinjie, Pack, Jordan, Swann, Joshua, Holtzman, Luke, Cothrine, Matthew, Watanabe, Kenji, Taniguchi, Takashi, Mandrus, David, Barmak, Katayun, Hone, James, Millis, Andrew J, Pasupathy, Abhay N, Dean, Cory R
• Format: Journal Article
• Language: English
• Published: 05.06.2024
• Subjects: Physics - Mesoscale and Nanoscale Physics; Physics - Strongly Correlated Electrons; Physics - Superconductivity
• DOI: 10.48550/arxiv.2406.03418

The discovery of superconductivity in twisted bilayer and twisted trilayer graphene has generated tremendous interest. The key feature of these systems is an interplay between interlayer coupling and a moir\'e superlattice that gives rise to low-energy flat bands with strong correlations. Flat bands can also be induced by moir\'e patterns in lattice-mismatched and or twisted heterostructures of other two-dimensional materials such as transition metal dichalcogenides (TMDs). Although a wide range of correlated phenomenon have indeed been observed in the moir\'e TMDs, robust demonstration of superconductivity has remained absent. Here we report superconductivity in 5 degree twisted bilayer WSe$_2$ (tWSe$_2$) with a maximum critical temperature of 426 mK. The superconducting state appears in a limited region of displacement field and density that is adjacent to a metallic state with Fermi surface reconstruction believed to arise from antiferromagnetic order. A sharp boundary is observed between the superconducting and magnetic phases at low temperature, reminiscent of spin-fluctuation mediated superconductivity. Our results establish that moir\'e flat-band superconductivity extends beyond graphene structures. Material properties that are absent in graphene but intrinsic among the TMDs such as a native band gap, large spin-orbit coupling, spin-valley locking, and magnetism offer the possibility to access a broader superconducting parameter space than graphene-only structures.