Electronic and optical properties of single-walled carbon nanotubes under a uniform transverse electric field: A first-principles study

Abstract

A systematic study on the effect of a transverse electric field on the optical properties of carbon nanotubes has been performed using density-functional calculations. The band gaps of the zigzag tubes decrease significantly as the electric field is increased. In the case of armchair tubes, the metallic band energy dispersion relation develops multivalleys at the Fermi level at high fields. The electric-field-induced changes in band dispersions lead to changes in optical properties as manifested in the dielectric functions. Some of the changes are not obvious. For example, a significant field-induced change in band gap can lead to small changes in dielectric functions in some special cases. Our results show that the armchair carbon nanotubes can be a promising material for electro-optical modulation device applications.