Eur. Phys. J. B 80, 469-475 (2011)
https://doi.org/10.1140/epjb/e2011-10822-x

Dimer-covering resonating-valence-bond treatment of single-walled zigzag carbon nanotubes

Departament de Física Fonamental, Facultat de Física and Institut de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 647, 08028-Barcelona, Catalonia, Spain

Corresponding author: ^a m.angels.garcia_bach@ub.edu

Received: 27 October 2010
Revised: 24 February 2011
Published online: 30 March 2011

Abstract

Single-walled zigzag carbon nanotubes with h hexagons around the carbon nanotube, h ranging from 3 to 19, have been investigated from a resonating-valence-bond point of view. The energies calculated for the undoped h = 3n–1 zigzag carbon nanotubes, n integer, suggest that the two lowest-lying phases are degenerate. Therefore, de-confined low-energy topological spin defects would occur. Then, these carbon nanotubes should be conductors, in analogy to polyacethylene. In clear contrast, no such degeneracy is obtained for either, h = 3n+1 or h = 3n, so bound pairs of topological spin defects are expected to occur in these cases. Our findings provide further insights into electron correlation and exchange effects in carbon nanotubes.