Infrared absorption by achiral carbon nanotubes

Abstract

This work analyzes the effect of chirality on the frequency dependences of the real and imaginary parts of the dielectric function and the absorption coefficient of a single-walled carbon nanotube composite within the one-electron approximation. The calculations are performed for zigzag and armchair configurations of nanotubes. It is shown that the real part of the dielectric function and absorption coefficient for armchair-type nanotubes oscillate at lower frequencies because the energy intervals between the size-quantization levels decrease in this type of nanotube. When the frequencies of incident radiation coincide with the frequencies of interband transitions there is a resonant increase in the absorption coefficient of an achiral nanotube array. The size dependences of the absorption coefficient of the zigzag and armchair nanotube arrays are calculated, and their evolution with a change in the frequency of the incident electromagnetic wave is analyzed.