Superconductivity in the charge-transfer and Mott-Hubbard regimes of the three-band Hubbard model

An extensive quantum Monte Carlo calculation is performed to probe a possible electronic origin of the high-temperature superconductivity in cuprates by studying Emery's three-band Hubbard model. The dx2-y2 pairing correlation is found to grow with the system size when the d electron repulsion Ud or the d-p level off-set Δε exceed the one-electron band width, where the correlation also starts to increase with Ud or Δε. The authors have detected this in both the charge-transfer and Mott-Hubbard regimes for appropriate doping concentrations