Correlation-corrected energy bands of YBa{sub 2}Cu{sub 3}O{sub 7}: A mutually consistent treatment
- Chair for Theoretical Chemistry, Friedrich-Alexander-University, Erlangen-Nuernberg, Egerlandstr. 3, D-91058 Erlangen (Germany)
The band structures and density of states (DOS) of important subunits (Cu-O planes and 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 both subunits in a mutually consistent way embedding them also in a partially self-consistent Madelung potential of the 3D crystal. Afterwards the bands were corrected for correlation by a Green{close_quote}s-function method in second order of the Mo/ller-Plesset many-body perturbation theory. The main purpose of these rather large-scale calculations was to obtain reliable unfilled energy bands to be used in subsequent exciton bands calculations. This will make it possible to look more thoroughly at the proposed excitonic (polarization) mechanism of high-T{sub c} superconductivity. A comparison with calculations based on a local-density-functional (LDF) approximation showed good agreement to our approach in the valence-band energy region above {minus}8 eV while the LDF results agree well with experimental photoelectron spectra. In contrast to the LDF methods, we detected between {minus}8 and {minus}12 eV flat Cu3d energy bands, which correspond to satellite structures observed by experiment. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 541947
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 55, Issue 13; Other Information: PBD: Apr 1997
- Country of Publication:
- United States
- Language:
- English
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