Signatures of superconducting pairing driven by electron-electron interactions in moir\'e WSe$_2$/WSe$_2$ homobilayer modelled by Hubbard Hamiltonian

TL;DR

This paper models superconductivity in twisted WSe2/WSe2 bilayers using the Hubbard model and DMRG, revealing signatures of mixed-symmetry pairing driven by electron-electron interactions, consistent with recent experiments.

Contribution

It demonstrates that electronic correlations induce mixed-symmetry superconductivity in a Hubbard model of twisted WSe2/WSe2, providing theoretical insight into experimental observations.

Findings

Signatures of coexisting singlet and triplet pairings.

Superconductivity likely driven by electronic correlations.

Identification of specific superconducting order parameters.

Abstract

Strong evidence of unconventional superconductivity has been very recently reported experimentally in twisted transition metal dichalcogenide bilayer and gathered a significant amount of interest. Here we consider the Hubbard model on a triangular lattice describing the hole-doped moir\'e superlattice emerging in WSe$_{2}$/WSe$_{2}$ twisted homobilayer in the moderately correlated regime. By applying the Density Matrix Renormalization Group, we diagonalize the spin-valley-polarized Hamiltonian and show signatures of coexisting singlet and triplet pairings in the range of hole dopings and displacement fields reported in the experiments. In this view, we show that the superconductivity in the WSe$_{2}$/WSe$_{2}$ twisted homobilayer is likely to be induced by electronic correlations and has a mixed-symmetry character. These predictions can shed light on the nature of the superconducting state observed in the twisted homobilayer of WSe$_{2}$/WSe$_{2}$. We also identify the emerging superconducting orders, which are $d_{xy}(d_{x^2-y^2} \pm id_{xy} )$ and $p_y(p_{x}\mp ip_{y})$ for the singlet and triplet channels in the cylinder of width three(four), respectively.