The ‘magic’ electronic state of high-Tccuprate superconductors

Abstract

The available experimental data for 105 distinct families of high-T_coxocuprate superconductors point to the presence of a ‘magic’ intrasheet Cu–O separation of 1.923 Å, which yields the highest T_c values at ambient pressure (Rao 1995). The interpretation with Burdett's model (1993), along with electronic band structure calculations, is centered at a crossing of the O- and Cu-predominated σ bands and points to the significance of the electron–phonon coupling for these materials.