Electronic structure of single wall carbon nanotubes under transverse external electric field, radial deformations and defects

We present density functional theory and tight binding calculations of a radially deformed (8,0) single walled carbon nanotube under transverse external electric fields. Density functional theory calculations are also presented for radially deformed and defective (8,0) nanotube. Three types of single defects are considered – Stone-Wales, single Nitrogen impurity, and a mono-vacancy. The electronic structure and energy gap changes are explained in terms of orbital admixture in the total density of states and energy band structure as a function of deformation and fields strengths, types of defects, and/or curvature. Our results can be used to understand and interpret experimental data of realistic nanotubes under extreme conditions, as well as to engineer new or build on existing nanoelectronic devices.