Strong enhancement of p + ip and d + id topological superconductivity on a center-decorated honeycomb lattice

Abstract Using the constrained-path quantum Monte Carlo method, we investigate the superconducting and charge properties of the extended Hubbard model on a center-decorated honeycomb lattice, which includes nearest-neighbor attraction ( V 1 ) and third-nearest-neighbor attraction ( V 2 ) between sites on the hexagonal grid. Our simulations show that V 1 and V 2 act to strongly enhance the triplet p + ip and singlet d + id pairing correlations, respectively. Increasing charge density on the hexagonal grid leads to a competition between the dominant pairing symmetry and other symmetries. Further simulations indicate that such topological superconductivity (TSC) is suppressed when the hopping between decorated center and hexagonal grid becomes small, and is insensitive to the on-site Coulomb repulsion U at decorated center. The introduction of site disorder on the hexagonal grid renders a suppression of the dominant pairing symmetry. Simultaneously, we find that V 2 results in a pronounced increase of the charge structure factor at all wave vectors, with broad peaks developed at nonzero q , signifying the formation of short-range charge density waves. Our findings provide a promising route to the realization of TSC via decoration of hexagonal lattice.