Correlation-corrected energy bands of YBa{sub 2}Cu{sub 3}O{sub 7}: A mutually consistent treatment

摘要: The band structures and density of states (DOS) important subunits (Cu-O planes chains, both including apical oxygens) in YBa{sub 2}Cu{sub 3}O{sub 7} were computed. As a first step we employed an {ital ab initio} Hartree-Fock (HF) crystal-orbital method to mutually consistent way embedding them also partially self-consistent Madelung potential the 3D crystal. Afterwards bands corrected for correlation by Green{close_quote}s-function second order Mo/ller-Plesset many-body perturbation theory. main purpose these rather large-scale calculations was obtain reliable unfilled energy be used subsequent exciton calculations. This will make it possible look more thoroughly at proposed excitonic (polarization) mechanism high-T{sub c} superconductivity. A comparison with based on local-density-functional (LDF) approximation showed good agreement our approach valence-band region above {minus}8 eV while LDF results agree well experimental photoelectron spectra. In contrast methods, detected between {minus}12 flat Cu3d bands, which correspond satellite observed experiment. {copyright} 1997} American Physical Society}