Model for the role of oxygen defects in oxygen-defect superconductors

We propose that oxygen defects provide a mechanism for pairing enhancement in oxide-defect superconductors. A model is formulated and mean-field Gorkov equations are derived and solved numerically for a two-dimensional realization of the model. We show that very high-temperature critical temperatures are not difficult to understand in such models. Several experimental features of the superconducting oxides, including spin-glass-like properties, sensitivity to oxygen concentration, and temperature dependence of positron annihilation times, appear to be qualitatively consistent with such a model. © 1988 The American Physical Society.