Transition Temperatures in Cuprate Superconductors on the Basis ofd-pModel

On the basis of d - p model, both normal and anomalous self-energies are calculated perturbatively up to third order with respect to the Coulomb repulsion U between d -electrons at a Cu site. The superconducting transition temperature T c is obtained as a function of d - and p -hole numbers by the solution of the Dyson-Gor'kov equation. In the over-doped region, T c decreases with the increase of the total hole number δ . This experimentally obtained behavior of T c is successfully reproduced. In the under-doped region, T c decreases rapidly with the decrease of δ experimentally. Such a rapid change of T c is not obtained in our calculation, but it is found that T c is almost independent of δ by the suppression due to the vertex corrections.