We study the Cu5O4 cluster by exact diagonalization of a three-band Hubbard model and show that bound electron or hole pairs are obtained at appropriate fillings, and produce superconducting flux quantization. The results extend earlier cluster studies and illustrate a canonical transformation approach to pairing that we have developed recently for the full plane. The quasiparticles that in the many-body problem behave like Cooper pairs are W = 0 pairs, that is, two-hole eigenstates of the Hubbard Hamiltonian with vanishing on-site repulsion. The cluster allows W = 0 pairs of d symmetry, due to a spin fluctuation, and s symmetry, due to a charge fluctuation. Flux quantization is shown to be a manifestation of symmetry properties that hold for clusters of arbitrary size.

Cini, M., Balzarotti, A., Stefanucci, G. (2000). Pairing in the Hubbard model: the Cu5O4 cluster versus the Cu-O plane. THE EUROPEAN PHYSICAL JOURNAL. B, CONDENSED MATTER PHYSICS, 14(2), 269-280.

Pairing in the Hubbard model: the Cu5O4 cluster versus the Cu-O plane

CINI, MICHELE;BALZAROTTI, ADALBERTO;STEFANUCCI, GIANLUCA
2000-01-01

Abstract

We study the Cu5O4 cluster by exact diagonalization of a three-band Hubbard model and show that bound electron or hole pairs are obtained at appropriate fillings, and produce superconducting flux quantization. The results extend earlier cluster studies and illustrate a canonical transformation approach to pairing that we have developed recently for the full plane. The quasiparticles that in the many-body problem behave like Cooper pairs are W = 0 pairs, that is, two-hole eigenstates of the Hubbard Hamiltonian with vanishing on-site repulsion. The cluster allows W = 0 pairs of d symmetry, due to a spin fluctuation, and s symmetry, due to a charge fluctuation. Flux quantization is shown to be a manifestation of symmetry properties that hold for clusters of arbitrary size.
2000
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore FIS/03 - FISICA DELLA MATERIA
English
Con Impact Factor ISI
HIGH-TEMPERATURE SUPERCONDUCTORS; P-D MODEL; SYMMETRY; ELECTRONS; PSEUDOGAP; STATES
Cini, M., Balzarotti, A., Stefanucci, G. (2000). Pairing in the Hubbard model: the Cu5O4 cluster versus the Cu-O plane. THE EUROPEAN PHYSICAL JOURNAL. B, CONDENSED MATTER PHYSICS, 14(2), 269-280.
Cini, M; Balzarotti, A; Stefanucci, G
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/58633
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