Toy model of superconductivity
  The model of hypothetical superconductivity, where the energy gap asymptotically approaches zero as temperature or magnetic field increases, has been proposed. Formally the critical temperature and the second critical field for such a superconductor is equal to infinity. Thus the material is in superconducting state always. 
Konstantin V. Grigorishin, Bohdan I. Lev
cond-mat.supr-con