On-site repulsion as the source of pairing in carbon nanotubes and intercalated graphite
Istituto Nazionale per la Fisica della Materia,
Dipartimento di Fisica, Universita' di Roma Tor Vergata, Via della Ricerca Scientifica, 1-00133 Roma, Italy
Corresponding author: a email@example.com
Published online: 29 November 2002
We show that different non-conventional superconductors have one fundamental feature in common: pair eigenstates of the Hamiltonian are repulsion-free, the W=0 pairs. In extended Hubbard models, pairing can occur for reasonable parameter values. For (N,N) nanotubes the binding energy of the pair depends strongly on the filling and decreases towards a reduced but nonzero value for the graphite sheet .
PACS: 74.20.Mn – Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.) / 73.22.-f – Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals / 73.63.Fg – Nanotubes
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002