A microscopic model describing the electronic structure of carbon nanotubes formed from two-dimensional disordered graphite sheets is presented. The strong electronic-lattice coupling of states near the Fermi energy is shown to result in the formation of an energy gap. The model predicts that the energy gap in these tubes is inversely proportional to the diameter with a larger magnitude than in crystalline tubes. Our results are shown to be in good agreement with experimental data for carbon nanotubes containing considerable structural defects.

• Received 5 October 1999

DOI:https://doi.org/10.1103/PhysRevB.61.5793