Particle-particle response function as a probe for electronic correlations in the p-d Hubbard model

Journal Article · Sun Aug 15 00:00:00 EDT 2010 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.82.075137· OSTI ID:21421396

Ugenti, S ^[1]; Cini, M; Perfetto, E; Stefanucci, G ^[1]; Seibold, G ^[2]; Lorenzana, J ^[3]

---

1. Dipartimento di Fisica, Universita di Roma Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Rome (Italy)
2. Institut fuer Physik, BTU Cottbus, P.O. Box 101344, 03013 Cottbus (Germany)
3. ISC-CNR, Dipartimento di Fisica, Sapienza Universita di Roma, Piazzale Aldo Moro 2, I-00185 Rome (Italy)

We discuss and compare different approximations to the particle-particle response function in the p-d (three-band) Hubbard model for the CuO{sub 2} plane of superconducting cuprates. Besides the relevance for understanding the role of correlations in high-T{sub c} superconductors, the interest in the CuO{sub 2} plane is due to the presence of three incompletely filled valence bands. The bare ladder approximation (BLA) was employed long ago in the context of Auger core-valence-valence spectroscopy of late transition metals while the time-dependent (TD) Gutzwiller approximation (GA) is a much more sophisticated and recent development. The validity of both is assessed by comparing with exact-diagonalization results from a finite six-site cluster. We find that for standard parameter sets TDGA and BLA yield two-hole spectra in excellent agreement with the exact ones. Although the interaction is comparable to the kinetic energy, the system is far from the extreme Mott limit often assumed in cuprates, where the Mott insulating character is completely local. In order to identify possible fingerprints of the extreme Mott regime we artificially reduce the bandwidth. We find that the BLA breaks down while the TDGA keeps near the exact results. Our findings provide a simple criterion to identify doped and undoped extreme Mott insulators.

• OSTI ID: 21421396
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 82, Issue 7; Other Information: DOI: 10.1103/PhysRevB.82.075137; (c) 2010 The American Physical Society; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AUGER ELECTRON SPECTROSCOPY
COMPARATIVE EVALUATIONS
COPPER OXIDES
CORRELATIONS
CUPRATES
DOPED MATERIALS
HIGH-TC SUPERCONDUCTORS
HUBBARD MODEL
INTERACTIONS
KINETIC ENERGY
LADDER APPROXIMATION
RESPONSE FUNCTIONS
SPECTRA
SPECTROSCOPY
TIME DEPENDENCE
TRANSITION ELEMENTS
APPROXIMATIONS
CALCULATION METHODS
CHALCOGENIDES
COPPER COMPOUNDS
CRYSTAL MODELS
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY
EVALUATION
FUNCTIONS
MATERIALS
MATHEMATICAL MODELS
METALS
OXIDES
OXYGEN COMPOUNDS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
TYPE-II SUPERCONDUCTORS