High Tc Superconductivity: Doping Dependent Theory Confirmed by   Experiment
  A Hamiltonian H(\Gamma) applicable to cuprate HTS, with a doping dependent pairing interaction \Gamma(x) = V(x) + U(x), is linked to a Cu3d-O2p state probability model(SPM). A consequence of doping induced electron hopping, the SPM mandates that plaquettes with net charge and spin form in the CuO plane, establishing an effective spin-singlet exchange interaction U(x). The U(x) is determined from a set of probability functions that characterize the occupation of the single particle states. An exact treatment of the average static fluctuation part of H shows that diagonal matrix elements U_{k k} < 0 produce very effective pairing, with significant deviation from the mean field approximation, which also depends on a phonon-mediated interaction V. This deviation is primarily responsible for the diverse set of HTS properties. The SC phase transition boundary T_c(x), the SC gap \Delta(x), and the pseudogap \Delta_{pg}(x) are fundamentally related. Predictions are in excellent agreement with experiment, and a new class of HTS materials is proposed. Large static fluctuation results in extreme HTS and quantum criticality. 
Stephen B. Haley and Herman J. Fink
cond-mat.supr-con