Theory of unconventional superconductivity in gated monolayer WTe2

Recent observation of superconductivity in monolayer WTe2 upon gating has attracted much interest since the undoped WTe2 has been experimentally established as a quantum spin Hall insulator. Although the nature of the superconductivity remains elusive, the prevailing expectation is that inducing superconductivity in already topological materials is a promising route to identifying new exotic superconductors. Here we investigate the dominant pairing instabilities under different microscopic interactions by solving the linearized gap equation. We find equal-spin paired state that is consistent with the experimentally found high critical field, and we discuss the possibility of topological paired state. Finally, we consider the effects of a single impurity, as the first step towards determining how disorder impacts the phase diagram.