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 $\ensuremath{\delta}$ = 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 ${d}_{{x}²\ensuremath{-}{y}²}$-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., $\ensuremath{\delta}$ 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.