Superconducting pairing symmetry in doped honeycomb lattice

To explore electron correlation-driven superconductivity in doped graphene, we use constrained path quantum Monte Carlo method to study magnetic correlation and superconducting pairing correlation in t-U-V Hubbard model on a honeycomb lattice．At half-filling this system shows strong antiferromagnetic correlation．Antiferromagnetic correlation increases with Coulomb interaction U, but is suppressed with the nearest neighbor interaction V．Away from half-filling, next-nearest-neighbor d+id pairing symmetry dominates at low doping compared to other pairing symmetries, and is insensitive to small nearest-neighbor interaction V．A larger V will, however, significantly suppress next-nearest-neighbor d+id superconducting pairing correlation．These results may lead to further understanding of superconductivity states in twisted bilayer graphene．