ELECTRONIC-STRUCTURE OF THE 83-K SUPERCONDUCTOR BI2SR2CACU2O8

The occupied and unoccupied electronic structure of Bi2Sr2CaCu2O8 single crystals has been investigated by high resolution angle-resolved photoemission, applying synchrotron radiation of 18 eV, and angle-resolved inverse photoemission. The electronic states far from the Fermi level are almost dispersionless due to correlation effects. Near the Fermi level, a band reveals weak but distinct k¶; dispersion, crossing EF at about ½ ΓX. Starting for T > Tc on the Fermi surface, for T c spectral weight is shifted from EF to higher binding energy related to the opening of the superconducting gap of Δ = 30 meV. These findings strongly favour Fermi liquid based theories for high-Tc superconductivity in this material. © 1990 IOP Publishing Ltd.