Theory of Topological Superconductivity and Antiferromagnetic Correlated Insulators in Twisted Bilayer WSe₂

Since the very recent discovery of unconventional superconductivity in twisted WSe₂ homobilayers at filling ν=−1, considerable interests arise in revealing its mechanism. In this paper, we developed a three-band tight-binding model with non-trivial band topology by direct Wannierization of the low-energy continuum model. Incorporating both onsite Hubbard repulsion and next-nearest-neighbor attraction, we then performed a mean-field analysis of the microscopic model and obtained a phase diagram qualitatively consistent with the experiment results. For zero or weak displacement field, the ground state is a Chern number C=±2 topological superconductor in the Altland-Zirnbauer A-class (breaking time-reversal but preserving total S_z symmetry) with inter-valley pairing dominant in d_xy∓id_x²−y²-wave (mixing with a subdominant p_x±ip_y-wave) component. For a relatively strong displacement field, the ground state is a correlated insulator with 120° antiferromagnetic order. Our results provide new insights into the nature of the twisted WSe₂ systems and suggest the need for further theoretical and experimental explorations.