Superconductivity in a narrow-band system with intersite electron pairing in two dimensions: A mean-field study

Journal Article · Wed Jun 01 04:00:00 EDT 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.37.9410· OSTI ID:7247182

Micnas, R; Ranninger, J; Robaszkiewicz, S; Tabor, S

We study a simple model for superconductivity based on the extended Hubbard model with on-site repulsive and intersite attractive interaction for arbitrary electron density using the mean-field approach. We perform detailed numerical studies of anisotropic superconductivity of s, p, and d type for the two-dimensional square lattice with nearest- and next-nearest-neighbor hopping. For a nearly half-filled band the d-wave pairing is most stable. p-wave and then extended s-wave pairing become stable upon decreasing the band filling. While T/sub c/ for d- and p-wave pairings smoothly decrease with band filling, s-wave pairing shows strong nonmonotonic behavior of T/sub c/ versus electron density. Inclusion of next-nearest-neighbor hopping changes essentially the behavior of T/sub c/ and the mutual stability of anisotropic pairings. The competition between superconductivity and the spin-density-wave state is studied. The question of the transition from Cooper pairs to intersite pairs and their Bose condensation is discussed. We also consider the limit of strong correlations and its connection with recent theoretical proposals for the superconductivity in high-T/sub c/ oxides. Our findings are discussed in connection with the experimental studies of superconductivity and magnetism in La/sub 2/CuO/sub 4/-based compounds.

• Research Organization: Centre de Recherches sur les Tres Basses Temperatures, Centre National de la Recherche Scientifique, Boi-italic-circumflexte Postale 166 X, 38042 Grenoble-Cedex, France
• OSTI ID: 7247182
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 37:16; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

656100* -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
INTERACTIONS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MEAN-FIELD THEORY
OXIDES
OXYGEN COMPOUNDS
PAIRING INTERACTIONS
RARE EARTH COMPOUNDS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
TWO-DIMENSIONAL CALCULATIONS