Superconductor–Insulator Transition in the d–p Model

We investigate a transition between the superconducting phase and the Mott insulator phase in the d – p model by using the slave-boson method and the 1/ N -expansion theory, where the pairing interaction is given by the superexchange interaction J s . We show that the competition between the pairing interaction and the Fermi energy induces the transition at finite doping rate.