Phase diagram of the electron-doped cuprate superconductors

We investigate the T-delta phase diagram of the electron-doped systems in high-T-c cuprates where delta is doping rate. Taking the ingap state and the superexchange interaction J(s), we calculate the supercondtlcting transition temperature T-c, the antiferromagnetic transition temperature T-N, and the NMR relaxation rates 1/T-1 with the antiferromagnetic fluctuations in the fluctuatoin-exchange (FLEX) approximation and with the superconducting fluctuations in the self-consistent t-matrix approximation. The obtained phase diagram has features in common with those in the hole-doped systems, including the antiferromagnetic state, the superconducting state and the spin gap phenomenon. Doping dependences of T-N, T-C and T-SG (spin gap temperature) are, however, different from those in the hole-doped systems. These differences are due to the intrinsic nature of the ingap state, which have been shown in the d-p model. The ingap state is intimately related to the Zhang-Rice singlets in the hole-doped systems, while it corresponds to correlated d-electrons in the electron-doped systems.