Band-structure trend in hole-doped cuprates and correlation with T(c max).

By calculation and analysis of the bare conduction bands in a large number of hole-doped high-temperature superconductors, we have identified the range of the intralayer hopping as the essential, material-dependent parameter. It is controlled by the energy of the axial orbital, a hybrid between Cu 4s, apical-oxygen 2p(z), and farther orbitals. Materials with higher T(c max) have larger hopping ranges and axial orbitals more localized in the CuO2 layers.