Impurity-induced resonant state in a pseudogap, state of a high-T-c superconductor - art. no. 054501

We predict a resonance-impurity state generated by the substitution of one Cu atom with a nonmagnetic atom, such as Zn, in the pseudogap state of a hi gh-T-c superconductor. The precise microscopic origin of the pseudogap is n ot important for this state to be formed, in particular this resonance will be present even in the absence of superconducting fluctuations in the norm al state. In the presence of superconducting fluctuations, we predict the e xistence of a counterpart impurity peak on a symmetric bias. The nature of this impurity resonance is similar to the previously studied resonance in t he d-wave superconducting state.