Quantum Interferences in the Raman Cross Section for the Radial Breathing Mode in Metalic Carbon Nanotubes

TL;DR

This paper investigates how quantum interference effects influence the Raman excitation profiles of radial breathing modes in metallic carbon nanotubes, emphasizing the importance of accurate modeling for proper nanotube characterization.

Contribution

It demonstrates the significant impact of quantum interferences on Raman lineshapes in metallic nanotubes and highlights the necessity of including these effects for correct (n,m) index identification.

Findings

Interference effects alter Raman lineshapes in metallic nanotubes.

Proper modeling of interferences is essential for accurate nanotube characterization.

Electronic band structure features influence Raman spectral profiles.

Abstract

The lineshapes of the Raman excitation profiles for radial breathing modes in carbon nanotubes are shown to be strongly affected by interference effects that arise whenever strong optical transitions are separated by a small energy. This is the case in metallic zigzag and chiral tubes, where one-dimensional singularities in the electronic joint density of states are split due to the trigonal warping of the electronic band structure of two-dimensional graphene. It is shown that the proper modeling of these interferences is crucial for the identification of the (n,m) indices using Raman spectroscopy.