Apical oxygen ions and the electronic structure of the high- T sub c cuprates

Journal Article · Fri May 01 04:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.45.10647· OSTI ID:7113366

Feiner, L F ^[1]; Grilli, M; Di Castro, C ^[2]

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1. Philips Research Laboratories, P.O. Box 80000, 5600 JA Eindhoven (Netherlands)
2. Dipartimento di Fisica, Universita La Sapienza,'' Piazzale A. Moro 2, 00185 Roma (Italy)

We analyze a five-band extended Hubbard model involving four orbitals on the CuO{sub 2} planes of the high-temperature superconducting oxides ({ital d}{sub {ital x}}{sup 2}{minus}{ital y}{sup 2} and {ital d}{sub 3{ital z}}{sup 2}{minus}{ital r}{sup 2} for the copper, and 2{ital p}{sub {ital x}} and 2{ital p}{sub {ital y}} for the oxygen) and the 2{ital p}{sub {ital z}} orbital(s) for the out-of-plane apical oxygen ion(s). The strong local repulsion between holes on copper is treated by means of a slave-boson approach in mean-field approximation, whereas the nearest-neighbor Cu-O Coulombic repulsion is treated within a Hartree decoupling scheme. We systematically investigate the variation of the resulting band structure with doping and with varying model parameters, and examine its stability with respect to lattice deformations. The results are compared with experimental data on photoemission, polarized x-ray-absorption spectroscopy, electron-energy-loss spectroscopy, and optical absorption. We analyze in particular the effects of the apical oxygen(s) on the electronic structure, and we identify the amount {ital n}{sub {ital a}1} of holes in states with local {ital a}{sub 1} symmetry as the quantity most directly affected by their presence. This quantity differentiates between the various high-{ital T}{sub {ital c}} cuprates, which are otherwise very similar as far as the planar structure is concerned. An analysis of ten different classes of compounds reveals a correlation between the maximum critical temperature {ital T}{sub {ital c}}{sup max} attained within each class at the optimum doping {delta}{sup max} and the excess of {ital a}{sub 1} holes with respect to the doping itself {ital n}{sub {ital a}1}({delta}{sup max}){minus}{delta}{sup max}.

• OSTI ID: 7113366
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 45:18; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

665411* -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHARGED PARTICLES
COPPER COMPOUNDS
CUPRATES
D STATES
ELECTRONIC STRUCTURE
ENERGY LEVELS
HIGH-TC SUPERCONDUCTORS
HOLES
IONS
OXYGEN COMPOUNDS
OXYGEN IONS
P STATES
PHYSICAL PROPERTIES
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE