Cluster approach to the three-band Hubbard model of the Cu-O plane: Superconducting pairs

Journal Article · Mon Dec 01 04:00:00 EST 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.56.14711· OSTI ID:550546

Cini, M; Balzarotti, A ^[1]

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1. Istituto Nazionale di Fisica della Materia, Dipartimento di Fisica, Universita di Roma Tor Vergata, Via della Ricerca Scientifica 1- 00133 Roma (Italy)

The fully symmetric Cu-O clusters with a central Cu have two-hole singlet eigenstates which are not affected by the on-site repulsion. These pairs become bound states if the number of holes in the cluster is appropriate; moreover, the quantization at half-integer values of a magnetic test flux is consistent with a superconducting pattern. To investigate the mechanism of pairing, we study the symmetric clusters with {le}21 atoms and four holes by exact diagonalization. Further, by the diagrammatic expansion of the ground-state energy and of the scattering amplitude, we obtain the spin-flip diagrams for the effective interaction, which is attractive for singlets and repulsive for triplets. A criterion for pairing in cluster calculations is thereby obtained. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 550546
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 22 Vol. 56; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BOUND STATE
CLUSTER MODEL
COOPER PAIRS
EIGENFUNCTIONS
EIGENVALUES
HIGH-TC SUPERCONDUCTORS
HOLES
HUBBARD MODEL