Gorkov equations for a pseudogapped high-temperature superconductor - art.no. 144516

A phenomenological theory of superconductivity based on the two-body Cooper on propagator is presented. This theory takes the form of a modified Gorkov equation for the Green's function and allows one to model the effect of lo cal superconducting correlations and long-range phase fluctuations on the s pectral properties of high-temperature superconductors, both above and belo w T-c. A model is proposed for the Cooperon propagator, which provides a si mple physical picture of the pseudogap phenomenon, as well as insights into the doping dependence of the spectral properties. Numerical calculations o f the density of states and spectral functions based on this model are also presented, and compared with the experimental tunneling (STM) and photoemi ssion (ARPES) data. It is found, in particular, that the sharpness of the p eaks in the density of states is related to the strength and the range of t he superconducting correlations and that the apparent pseudogap in STM and ARPES can be different, although the underlying model is the same.