Superconductivity in 5.0° twisted bilayer WSe.

The discovery of superconductivity in twisted bilayer and trilayer graphene has generated tremendous interest. The key feature of these systems is an interplay between interlayer coupling and a moiré superlattice that gives rise to low-energy flat bands with strong correlations. Flat bands can also be induced by moiré 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 phenomena have indeed been observed in moiré TMDs, robust demonstration of superconductivity has remained absent. Here we report superconductivity in 5.0° twisted bilayer WSe 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 a Fermi surface reconstruction believed to arise from AFM 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 moiré flat-band superconductivity extends beyond graphene structures. Material properties that are absent in graphene but intrinsic among TMDs, such as a native band gap, large spin-orbit coupling, spin-valley locking and magnetism, offer the possibility of accessing a broader superconducting parameter space than graphene-only structures.