Springer LINK: The European Physical Journal B - Abstract Volume 5 Issue 3 (1998) pp 371-378

The European Physical Journal B

ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)

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Abstract Volume 5 Issue 3 (1998) pp 371-378

Superconductivity with s and p symmetries in an extended Hubbard model with correlated hopping

A.A. Aligia (1), E. Gagliano (1), L. Arrachea (2), K. Hallberg (1) (a)

(1) Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, 8400 Bariloche, Argentina
(2) Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Strasse 38, 01187 Dresden, Germany

Received: 2 February 1998 / Accepted: 17 March 1998

Abstract: We consider a generalized Hubbard model with on-site and nearest-neighbour repulsions U and V respectively, and nearest-neighbour hopping for spin up (down) which depends on the total occupation n_b of spin down (up) electrons on both sites involved. The hopping parameters are t_AA, t_AB and t_BB for n_b=0,1,2 respectively. We briefly summarize results which support that the model exhibits s-wave superconductivity for certain parameters and extend them by studying the Berry phases. Using a generalized Hartree-Fock(HF) BCS decoupling of the two and three-body terms, we obtain that at half filling, for t_AB<t_AA=t_BB and sufficiently small U and V the model leads to triplet p-wave superconductivity for a simple cubic lattice in any dimension. In one dimension, the resulting phase diagram is compared with that obtained numerically using two quantized Berry phases (topological numbers) as order parameters. While this novel method supports the previous results, there are quantitative differences.

PACS. 74.20.Mn Nonconventional mechanics (spin fluctuations, polarons and bipolarons, resonating valence bound model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.) - 71.10.-w Theories and models of many electron systems - 71.27.+a Strongly correlated electron systems; heavy fermions

(a) email: karen@cab.cnea.edu.ar

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