d-wave to s-wave to normal metal transitions in disordered   superconductors
  We study suppression of superconductivity by disorder in d-wave superconductors, and predict the existence of (at least) two sequential low temperature transitions as a function of increasing disorder: a d -wave to -wave, and then an s-wave to metal transition. This is a universal property of the system which is independent of the sign of the interaction constant in the s-channel 
B. Spivak, P. Oreto, S. A. Kivelson