In this paper we first describe the multi-configuration self-consistent field method with configuration interaction (MCSCF-CI) which is a variational method most suitable for strongly-correlated cluster systems. Then the calculated results of CuO6 cluster embedded in hole-doped La2-xSrxCuO4 and of CuC4 cluster in the electron-doped Nd2-xCexCuC4 are reviewed. Finally the calculated results on the electronic structure of CuO5 pyramid embedded in the insulating YBa2Cu3O6 and superconducting YBa2Cu3O7 are newly presented. In the latter case we will clarify an important role of the Cu-O chain in the electronic and superconducting state of YBa2Cu3O7.
ASJC Scopus subject areas
- Statistical and Nonlinear Physics
- Condensed Matter Physics