Dominant p -wave pairing induced by nearest-neighbor attraction in the square-lattice extended Hubbard model

The two-dimensional Hubbard model is widely believed to capture the key ingredients of high-temperature superconductivity in cuprate materials. Here we report a constrained path quantum Monte Carlo study of the square-lattice extended Hubbard model with on-site Coulomb repulsion U and nearest-neighbor (NN) electron attraction V. Upon doping δ = 0.125, we find that NN electron attraction V significantly promotes an exotic spin-triplet (p-wave) pairing, with the p-wave pairing correlations growing stronger as V increases. Meanwhile, the dx2-y2-wave (d-wave) pairing in the intermediate coupling regime shows an insignificant response to the increase of V. The spin density wave order, which is observed near half filling in the particle-hole channel, is also almost unaffected by the NN electron attraction V, reinforcing the established relationship between d-wave superconductivity (SC) and spin order. As the doping becomes heavier (i.e., δ increases), the dominant region of p-wave pairing expands, further suppressing the presence of d-wave pairing. Our paper suggests the p-wave pairing region can be induced and further broadened by the NN electron attraction V, offering a feasible mechanism to realize p-wave SC in realistic cuprate materials.