d-wave pairing in the presence of long-range Coulomb interactions

The one-band extended Hubbard model in two dimensions near band-filling 1/2 is solved in the fluctuation exchange approximation, including the long-range (1/r) part of the Coulomb interaction, up to 4th-neighbor distance. Our results suggest that d(x2-y2) pairing in the Hubbard model is robust against the inclusion of long-range Coulomb interactions with moderate Ist-neighbor repulsion strength V-1. d(x)(-y)(2)(2) pairing is suppressed only at large V-1 (greater than or similar to 0.25U-0.4U), due to incipient charge density wave instabilities, [S0031-9007(99)08367-7].