Mechanism of superconductivity in twisted bilayer WSe2
In plain words
Twisted WSe2 superconducts at twist angles near 3.65 and 5 degrees, next to insulating or possibly magnetic states, and the attraction that pairs its electrons is unknown.
Precise statement
In twisted bilayer WSe2 at $\theta \sim 3.65\,\mathrm{deg}$ and $\sim 5\,\mathrm{deg}$, superconductivity with $T_c$ of a few hundred mK appears near half filling of the top moire band under displacement field, adjacent to a correlated insulator or metal with possible antiferromagnetic order. Determine the pairing interaction (spin fluctuations of a triangular-lattice Hubbard model, valley fluctuations, phonons) and the gap symmetry. An answer reproduces $T_c$ versus displacement field and filling from a microscopic model.
What would settle it
A gap-symmetry measurement plus identification of the adjacent ordered state, and a calculation reproducing the superconducting dome.
Status in the literature
Unverified note
Reported in 2024-2025 by Cornell (3.65 deg) and Columbia (5.0 deg) groups; a 2026 preprint reports superconductivity in twisted trilayer WSe2 (arXiv:2606.11495).