The Effect of Structural Distortions on the Electronic Structure of Carbon Nanotubes

TL;DR

This study investigates how structural distortions, such as bending, alter the electronic properties of carbon nanotubes, revealing increased state mixing, density-of-states changes, and potential electron localization effects.

Contribution

It provides a detailed analysis of how bending-induced distortions modify the electronic structure and charge distribution in carbon nanotubes, highlighting new effects of structural deformation.

Findings

Increased sigma and pi state mixing due to bending.

Enhanced density of states near the Fermi energy.

Charge polarization and potential electron localization.

Abstract

We calculated the effects of structural distortions on the electronic structure of carbon nanotubes. The key modification of the electronic structure brought about by bending a nanotube involves an increased mixing of $\sigma$ and $\pi$-states. This mixing leads to an enhanced density-of-states in the valence band near the Fermi energy region. While in a straight tube the states accessible for electrical conduction are essentially pure C($2p_{\pi}$)-states, they acquire significant C($2sp_{\sigma}$) 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 at low temperatures.