Resonant impurity scattering states in the pseudo-gap phase of high-temperature superconductors

Full text: We discuss resonant impurity scattering states in the pseudo-gap phase of high-temperature superconductors (HTSC). Within a T-matrix approach we calculate the spatial and energetic structure of the quasiparticle scattering resonances for different theoretical models of the pseudo-gap phase such as d-density wave and preformed pair state. Since the structure depends crucially on the environment from which the resonances arise our results demonstrate how different models for the pseudo-gap phase can be distinguished experimentally by scanning tunneling microscopy (STM). (author)