Electronic structure of Bi2Sr2CaCu2 O8 high-Tc superconductors

We compare the energy-band structure of the Tc=85 K phase of Bi2Sr2CaCu2 O8 with that of nonsuperconducting La2SrCu2O6, which has an analogous double-perovskite structure but lacks the Bi-O intergrowths. We also compare the band structures of two alternate Bi2Sr2CaCu2 O8 crystal structures to illustrate the consequences of rearranging the O atoms in the Bi-O intergrowth region. Finally, we discuss the effects of Bi-O intergrowths, modulated Bi-O layers, and changes in the number of CuO2 layers on the band structure and on superconductivity. © 1988 The American Physical Society.