Dynamical Spin Susceptibility of Electron-Doped High-Tc Cuprates-Comparison with Hole-Doped Systems

The magnetic excitation spectrum of electron-doped copper oxide superconductors is studied by calculating the dynamical spin susceptibility of the two-dimensional Hubbard model in which a d(x2-y2)-wave superconducting order parameter is assumed. The spectrum of electron-doped systems is compared with that of hole-doped systems. and the relationship between the frequency at which a peak grows in the spectrum and the superconducting energy gap at a hot spot is investigated. A peak may be observed even when the magnetic resonance condition is not exactly satisfied. We find that, in the electron-doped systems, the resonance condition is less likely to he satisfied than in the hole-doped systems because of the small density of stales around the hot spots, and the peak frequency is close to twice the gap magnitude at the hot spots.