Pairing symmetry with interband interaction

Abstract

We investigate the superconductivity of highTc oxides with the dp model. It is shown that the dp pairing can dominate the superconductivity. The pairing symmetry depends on the anisotropic dp interaction in CuO2 plane. The anisotropic dp interaction can lead to dwave or swave symmetry, but the repulsive interaction in the CuO2 plane cannot lead holes to being paired. The ‘preliminary pairing' may appear in a lightly doped regime. The critical temperature cannot be found for the pairing order parameter when the pairs are localized. The delocalization of holes and evolution of pairing symmetry with increasing doping are explained.