Theory for superconducting properties of the cuprates: doping dependence of the electronic excitations and shadow states

The superconducting phase of the 2D one-band Hubbard model is studied within the FLEX approximation and by using an Eliashberg theory. We investigate the doping dependence of Tc, of the gap function Δ(k,ω) and of the effective pairing interaction. Thus we find that Tc becomes maximal for 13% doping. In overdoped systems Tc decreases due to the weakening of the antiferromagnetic correlations, while in the underdoped systems due to the decreasing quasi-particle lifetimes. Furthermore, we find shadow states below Tc which affect the electronic excitation spectrum and lead to fine structure in photoemission experiments.