2026/07/17 by Chenyuan Li, Rwik Dutta, Fang Xie +4
#cond-mat.str-el
Recent observations of superconductivity in twisted bilayer WSe2 (tWSe2) have motivated theoretical proposals for unconventional pairing mechanisms. A central question is whether band topology plays an essential role in the system's correlation physics. In this letter, we develop a first-principles-based description of the top moiré valence bands in tWSe2. Using density functional theory (DFT) calculations, we identify the bands in the relevant range of twist angles to be topologically non-trivial, with the top valence bands carrying Chern numbers C=(+1,+1) for the K valley. In order to treat the strong correlation physics, we construct compact molecular orbitals directly from the DFT wave functions through a partial Wannierization procedure and with the guidance of spinful C3z symmetry representations. This yields a localized f orbital together with a complementary topological c orbital, allowing us to extract hopping and hybridization amplitudes from first principles. The resulting parameters provide an ab initio benchmark for the effective Hamiltonian. Our work establishes a foundation for understanding superconductivity in moiré TMDs and highlights tWSe2 as a promising platform for exploring topological superconductivity.