We study an extended version of the Anderson lattice model including a density-density attractive interaction between correlated electrons on nearest-neighbor sites. Using a perturbative expansion around the atomic limit for the normal phase and the broken-symmetry Hartree-Fock scheme for the attractive potential, we examine which of the possible symmetries of the superconducting order parameter leads to the highest transition temperatures, in the case of nearest-neighbor hopping on a square lattice. We find that in a wide range of electron densities around the half filling, the increase of the on-site Coulomb f-repulsion U changes the pairing symmetry from d-wave into p- or into anisotropic s-wave, depending on the parameter regime. For large values of U compared to the bandwidth, the superconducting phase is suppressed, regardless of the symmetry of the order parameter. The effects introduced by variations in the hybridization coupling are also analyzed.

Symmetry of the superconducting order parameter in the Anderson lattice model with nearest-neighbor attractive interaction

ROMANO, Alfonso;NOCE, Canio;
1997

Abstract

We study an extended version of the Anderson lattice model including a density-density attractive interaction between correlated electrons on nearest-neighbor sites. Using a perturbative expansion around the atomic limit for the normal phase and the broken-symmetry Hartree-Fock scheme for the attractive potential, we examine which of the possible symmetries of the superconducting order parameter leads to the highest transition temperatures, in the case of nearest-neighbor hopping on a square lattice. We find that in a wide range of electron densities around the half filling, the increase of the on-site Coulomb f-repulsion U changes the pairing symmetry from d-wave into p- or into anisotropic s-wave, depending on the parameter regime. For large values of U compared to the bandwidth, the superconducting phase is suppressed, regardless of the symmetry of the order parameter. The effects introduced by variations in the hybridization coupling are also analyzed.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11386/4363253
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