Doping dependence of hole-number distribution on CuO₂ plane and superconducting transition temperature of high-T_c cuprates by d_xy pairing scenario

The doping dependence of the hole-number distribution on the CuO₂ plane and the superconducting transition temperature T_c is investigated using the two-dimensional d-p model on the basis of a renormalized perturbation of the Fermi liquid: first forming the quasiparticles variationally by the Gutzwiller approximation taking into account the strong on-site repulsion U_d at Cu sites, then treating the residual interactions among quasiparticles by the RPA. The Gutzwiller variational state describes well the electronic state around the Fermi level and accounts for the systematic doping dependence of the hole-number distribution on Cu and O sites which has been measured by Asayama et al. using the NQR technique. Then the doping dependence of T_c is naturally understood by the charge-fluctuation mediated d_xy pairing scenario where the role of the repulsive interaction U_pd between the nearest-neighbor Cu and O sites is crucial.