Role of band mixing on superconductivity in two-dimensional system

Assuming that the p-states of O are involved in superconductivity in oxide superconductor and using the BCS approximation to the pairing interaction the effect of the mixing between the p-orbital of O and d-orbital of Cu on superconductivity is examined. It is found that superconductivity vanishes beyond a critical value of hybridization (Vc) that depends on charge transfer energy gap. Hybridization induces a pairing correlation Δ0/Tc between d-electrons and it vanishes at V=0 and Vc passing through a maximum. The ratio (Δ0/Tc) deviates from the BCS value before it goes to zero at Vc. (author). 14 refs., 3 figs