Model of a hypothetical high-temperature superconductor
  We propose a model of a hypothetical superconductor which includes impurities with retarded interaction with quasiparticle and superconducting matrix where these impurity can be applied with large concentration. Interaction between the impurity and a conduction electron in such a system has been calculated. We have found the critical temperature of the system matrix+impurity essentially exceeds critical temperature of the pure superconducting matrix. 
K.V. Grigorishin
cond-mat.supr-con