Comparison of effective models for CuO/sub 2/ layers in oxide superconductors

Journal Article · Tue Aug 01 04:00:00 EDT 1989 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.40.2239· OSTI ID:6050963

Ramak, A; Prelovek, P

Several effective models, as derived from a general two-band Hubbard model for CuO/sub 2/ layers in oxide superconductors, are studied. In particular, we compare the Hubbard model with the hole-spin models (unsymmetrized and symmetrized) and a generalized effective single-band (/ital t/-/ital J/) model. The exact calculation of energy spectra on a chain of four cells shows that states for a single additional hole are quite well reproduced by reduced models, taking into account the renormalization of constants. Less satisfactory is the agreement for the undoped system, especially for small charge-transfer energies. The same analytical procedure is applied to the square lattice system, where the parameters are estimated also from the levels of a single CuO/sub 4/ group. The results for quasiparticle spectra indicate that corrections to the /ital t/-/ital J/ model are even smaller than in the case of the single-band Hubbard model.

• Research Organization: J. Stefan Institute and Department of Physics, University of Ljubljana, 61111 Ljubljana, Yugoslavia (YU)
• OSTI ID: 6050963
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 40:4; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
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& Refractories-- Physical Properties
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BAND THEORY
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
OXIDES
OXYGEN COMPOUNDS
QUASI PARTICLES
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS