ELECTRONIC-STRUCTURE OF THE YBA2CU3O7 SUPERCONDUCTOR CONTAINING TWIN BOUNDARIES

Based on our structural model and a tight-binding Hamiltonian the electronic structure of the superconductor YBa2Cu3O7 has been calculated by the use of a recursion method. Compared with the single crystal, we mainly analyzed the feature of the electronic structure showing the twin boundary and evaluated the probability of various configurations of Cu and O ions, the type of the hybridization bonds, and various [Cu-O]+ complexes in superconducting ceramics. Meanwhile, we indicate that the twin boundary may be closely related to an electron deficiency. © 1990 The American Physical Society.