https://doi.org/10.1007/s100510050456
Superconductivity with s and p symmetries in an extended Hubbard model with correlated hopping*
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
Corresponding author: a karen@cab.cnea.edu.ar
Received:
2
February
1998
Accepted:
17
March
1998
Published online: 15 October 1998
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 nb of
spin down (up) electrons on both sites involved. The hopping parameters are , tAB and tBB for
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
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
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1998