The effect of structural distortions on the electronic structure of carbon nanotubes

We calculated the effects of structural distortions on the electronic structure of carbon nanotubes. The main effect of nanotube bending is an increased mixing of σ and π states. This mixing leads to an enhanced density-of-states in the valence band near the Fermi energy. While in a straight tube the states accessible for electrical conduction are essentially pure C(2pπ) states, they acquire significant C(2spσ) character upon bending. Bending also leads to a charge polarization of the C-C bonds in the deformed region reminiscent of interface dipole formation. Scattering of conduction electrons at the distorted regions may lead to electron localization.