Many-body effects on the electronic and optical properties of strained semiconducting carbon nanotubes

TL;DR

This study uses advanced many-body ab initio calculations to explore how uniaxial strain affects the electronic and optical properties of semiconducting zigzag carbon nanotubes, revealing complex bandgap behavior and strain-dependent excitonic effects.

Contribution

It provides a detailed analysis of strain effects on quasiparticle bandgaps and excitons in carbon nanotubes using GW and Bethe-Salpeter methods, surpassing previous models.

Findings

Electronic bandgaps have complex strain dependence.

Exciton energies and binding energies vary significantly with strain.

Optical absorbance remains nearly unaffected by strain.

Abstract

We present many-body \textit{ab initio} calculations of the electronic and optical properties of semiconducting zigzag carbon nanotubes under uniaxial strain. The GW approach is utilized to obtain the quasiparticle bandgaps and is combined with the Bethe-Salpeter equation to obtain the optical absorption spectrum. We find that the dependence of the electronic bandgaps on strain is more complex than previously predicted based on tight-binding models or density-functional theory. In addition, we show that the exciton energy and exciton binding energy depend significantly on strain, with variations of tens of meVs per percent strain, but that despite these strong changes the absorbance is found to be nearly independent of strain. Our results provide new guidance for the understanding and design of optomechanical systems based on carbon nanotubes.