Speaker
Description
Moiré materials constitute a highly tunable platform to investigate strongly correlated phenomena. In recent experiments, superconductivity was observed in the moiré material twisted WSe2, which extends the material families of superconductors and promises to advance our understanding of this intricate many-body quantum state. Superconductivity in twisted WSe2 appears next to an interaction-induced insulator and is tunable via an external displacement field. We analyze the correlated electron phases in twisted bilayer WSe2 at hole filling -1 and twist angle 3.65 using functional renormalization group calculations and investigate the dependence on model input. The advantage of using functional renormalisation here is that it treats the different ordering tendencies on equal footing and can detect superconductivity from repulsive bare interactions. We compare the instabilities obtained from a continuum model with gate-screened Coulomb interaction and a three-orbital Wannier model with Hubbard interaction, which we derive from first principles. In both cases, we find a superconducting instability with a mixed d-wave singlet and p-wave triplet symmetry arising adjacent to inter-valley coherent spin density wave order in the phase diagram for varying displacement field and interaction strength. We argue that the pairing mechanism is consistent with inter-valley coherent spin fluctuations as pairing glue. We show that the size and critical temperatures of the pairing regime change depending on the model input, and we argue that the main difference comes from the range and quantum geometry entering the projected interaction. In particular, we obtain pairing down to zero displacement field from the Coulomb interaction within the continuum model, reconciling theory and experiment.