Optical, magnetic, and single-particle excitations in the multiband Hubbard model for cuprate superconductors

Journal Article · Wed May 01 04:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.10517· OSTI ID:5589128

Wagner, J ^[1]; Hanke, W; Scalapino, D J ^[2]

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1. Physikalisches Institut, Universitaet Wuerzburg, Am Hubland, D-8700 Wuerzburg, Germany (DD)
2. Department of Physics, University of California, Santa Barbara, California 93106 (USA)

On the basis of exact diagonalizations, a comparative study of two-particle optical and magnetic, as well as single-particle, excitations is presented for a two-dimensional (2D) multiorbital Hubbard model. For reasonable parameter sets appropriate for the cuprate superconductors, the single-particle excitations display strongly correlated states related to the Zhang-Rice Cu-O singlet construction. These states define the gap (to the upper Hubbard band) at half-filling and become partially occupied by doping holes in our 2{times}2 unit-cell system. The optical results, which are the first quantitative calculations performed for realistic parameters of the three-band Hubbard model, clearly show three allowed optical transitions: (i) itinerant motion of the Cu-O singlets, having (for doping concentrations {ital x}{ne}0) a spectral Drude distribution around {omega}=0 with spectral weight proportional to {ital x}; (ii) unbinding of the O hole from the Cu spin in the singlet. This gives, in particular, a strong absorption peak due to singlet{r arrow}nonbonding oxygen transitions, again with relative weight {similar to}{ital x}.

• OSTI ID: 5589128
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 43:13; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

656100* -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COPPER COMPOUNDS
CUPRATES
ENERGY-LEVEL TRANSITIONS
EXCITATION
HIGH-TC SUPERCONDUCTORS
MAGNETO-OPTICAL EFFECTS
OPTICAL PROPERTIES
OSCILLATION MODES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SINGLE-PARTICLE MODES
STRUCTURAL MODELS
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE