Two-hole quasiparticles and pairing in the Hubbard model of high- superconducting cuprates
Michele Cini; Adalberto Balzarotti; Michele Cini; INFM, Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 1-00133 Roma, Italy; Adalberto Balzarotti; INFM, Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 1-00133 Roma, Italy
Журнал:
Journal of Physics: Condensed Matter
Дата:
1996-04-22
Аннотация:
We propose a configuration interaction mechanism that leads to hole pairs with zero repulsion energy which are exact eigenstates of the two-band Hubbard Hamiltonian. The two-hole pairs have symmetry and arise from degenerate states at the Fermi level; we show that they must exist independently of the band filling. To discuss the possible relevance of these states to the problem of pairing in high- superconductors we solve five- and nine-site model clusters with four holes. The quasiparticles become dressed by the interaction with the background holes and get paired with a set of valence band parameters well established for high- cuprates. We predict a number of important experimental facts such as binding energies of the correct order of magnitude, the symmetry of the order parameter and the singlet - triplet energy separation of the Cooper pairs.
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