Chiral Symmetry of Double-Walled Carbon Nanotubes detected in First-principles Optical Absorption Spectra

TL;DR

This study demonstrates that the chiral symmetries of both inner and outer tubes in double-walled carbon nanotubes can be identified through their optical absorption spectra, providing a precise experimental method for chiral angle measurement.

Contribution

It introduces a combined computational approach using tight-binding, sum-over-state, and first-principles calculations to detect chiral symmetries in DWNTs via optical spectra.

Findings

Characteristic peaks in absorption spectra reveal chiral symmetries.

The method allows precise measurement of the inner tube's chiral angle.

Chiral symmetry detection is robust regardless of outer tube type.

Abstract

The linear polarizability absorption spectra of the double-walled carbon nanotubes (DWNTs) have been calculated by using the tight-binding (TB) model and sum-over-state (SOS) method, supplemented by the first principles CASTEP calculations. It is found that the chiral symmetries of both outer and inner tubes in the DWNTs can always be identified distinctly by the characteristic peaks in the absorption spectra of the DWNTs, no matter what kind of the outer tube is, offering a powerful experimental tool to measure precisely the chiral angle of the inner tube of a DWNT.