Van Hove Non-Fermi Superconductors and Critical Temperature Degradation

We analyzed the non-Fermi behavior of copper oxides superconductors with an energy-dependent density of states of the van Hove (logarithmic) form, using the model proposed by Anderson and Yin and Chakravarty. The critical temperature degradation, due to a small amount of non-magnetic impurities, is also analyzed. It is shown that the decrease of the critical temperature is not of the Abrikosov–Gorkov type.