On the role of holes in the p-d anti-bonding band of CuO 2 planes for high- T c-superconductivity

Abstract

It is argued that the superconducting transition-temperature T c in the ceramics is controlled by the number of holes n h in the p-d hybridized antibonding band of the CuO 2-planes. T c(n h) regulates also the pressure dependence ( ∂T c ∂p ). The increase in T c for YBa 2Cu 3O 7 results partly from the Cu(1)O(4) chains which act as dopants of holes for the CuO 2 planes which contribute dominantly to superconductivity. Higher T c values in the Bi 2(Tl 2)Sr 2CaCu 2O 8-systems should result from further increase in the number of holes in the CuO 2 planes. We discuss T c(x, y ) of YBa 2( Cu 1− x M x ) 3 O 7− y , ( M = Ga, Zn) in terms of T c(n h) .