Abstract
Hybridization of the and states of the graphene network is shown to be as important as band-folding effects in determining the metallicity of small radius carbon nanotubes. Using detailed plane-wave ab initio pseudopotential local density functional (LDA) calculations, we find that the electronic properties of small tubes are significantly altered from those obtained in previous tight-binding calculations. Strongly modified low-lying conduction band states are introduced into the band gap of insulating tubes because of strong hybridization. As a result, the LDA gaps of some tubes are lowered by more than 50%, and a tube previously predicted to be semiconducting is shown to be metallic.
- Received 11 November 1993
DOI:https://doi.org/10.1103/PhysRevLett.72.1878
©1994 American Physical Society