Corrections to the Optical Transition Energies in Single-Wall Carbon Nanotubes of Smaller Diameters

TLDR: In this paper, a non-orthogonal density-functional based tight-binding calculation for the electronic transition energies in single-wall carbon nanotubes is presented. But the method does not consider the curvature-induced rehybridization of the electronic orbitals, long-range atomic interactions, and geometrical structure relaxation all have a significant impact on the transition energy in the small diameter limit, and the results show good agreement with the experimental transition energies observed by photoluminescence and resonance Raman spectroscopy.

Abstract: Optical spectroscopy characterization of carbon nanotube samples requires accurate determination of their band structure and exciton binding energies. In this paper, we present a non-orthogonal density-functional based tight-binding calculation for the electronic transition energies in single-wall carbon nanotubes. We show that the curvature-induced rehybridization of the electronic orbitals, long-range atomic interactions, and geometrical structure relaxation all have a significant impact on the electronic transition energies in the small diameter limit. After including quasiparticle corrections and exciton binding energies, the calculated electronic transition energies show good agreement with the experimental transition energies observed by photoluminescence and resonance Raman spectroscopy.