Interband optical transitions in left- and right-handed single-wall carbon nanotubes

Abstract

The nanotube handedness is defined for the complete determination of the nanotube atomic structure by its diameter and chirality. The interband electronic optical transition matrix elements are calculated and the dipole selection rules are derived for chiral carbon nanotubes and circularly polarized light propagating along the nanotube axis. The dipole selection rules are shown to depend on the nanotube handedness and on the helicity of the light, and this dependence is responsible for the optical activity of carbon nanotubes, when time-reversal symmetry is broken. The optical absorption spectra calculated for opposite light helicity or nanotube handedness show circular dichroism in chiral nanotubes. The optical activity of chiral nanotubes allows the nanotube handedness to be determined in optical experiments using circularly polarized light.