Europhys. Lett.
Volume 61, Number 4, February 2003
Page(s) 513 - 519
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 February 2003
DOI: 10.1209/epl/i2003-00159-8
Europhys. Lett., 61 (4) , pp. 513-519 (2003)

Correlation gap in armchair carbon nanotubes

T. A. Gloor and F. Mila

Institut de Physique Théorique, Université de Lausanne CH-1015 Lausanne, Switzerland

(Received 1 October 2002; accepted in final form 9 December 2002)

We revisit the problem of the correlation gap in (n,n) armchair carbon nanotubes, that would be metallic in the absence of electron-electron correlations. We attack the problem in the context of a Hubbard model with on-site repulsion U only, and we show that the scaling of the gap as $\exp[-nt/U]$ predicted by Balents and Fisher (Phys. Rev. B, 55 (1997) R11973) can only be valid if U is not too large, even for very large values of n. Using Hartree-Fock calculations and renormalisation group arguments we derive the scaling of the gap as a function of n for a given value of U. Possible applications for the magnitude of the correlation gap in armchair carbon nanotubes will be discussed.

71.10.Pm - Fermions in reduced dimensions (anyons, composite fermions, Luttinger liquid, etc.).
71.20.Tx - Fullerenes and related materials; intercalation compounds.
72.80.Rj - Fullerenes and related materials.

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