Pair-breaking effects in the Pseudogap Regime: Application to High   Temperature Superconductors
  Abrikosov-Gor'kov (AG) theory, the foundation for understanding pair-breaking effects in conventional superconductors, is inadequate when there is an excitation gap (pseudogap) present at the onset of superconductivity. In this paper we present an extension of AG theory within two important, and diametrically opposite approaches to the cuprate pseudogap. The effects of impurities on the pseudogap onset temperature T* and on Tc, along with comparisons to experiment are addressed. 
Ying-Jer Kao, Andrew P. Iyengar, Jelena Stajic and K. Levin