Topological Chiral Superconductivity Mediated by Intervalley Antiferromagnetic Fluctuations in Twisted Bilayer WSe_{2}.

Motivated by the recent observations of superconductivity in twisted bilayer WSe_{2} (tWSe_{2}), we theoretically investigate the superconductivity driven by an electronic mechanism. We first demonstrate that the multiband screened Coulomb interaction within the random phase approximation is insufficient to induce observable pairing instability. Nevertheless, by further including the intervalley antiferromagnetic fluctuations, the pairing interaction is substantially enhanced, yielding superconductivity with critical temperature T_{c} of hundreds of millikelvin at Van Hove singularities. The predicted T_{c} increases with increasing the displacement field and corresponds to a doubly degenerate d-wavelike pairing, which evolves into a topological chiral d±id superconductor below T_{c}. The interplay between superconductivity and intervalley antiferromagnetism results in a phase diagram consistent with experimental observations. These findings provide strong support for intervalley fluctuations as the primary pairing glue in tWSe_{2}.