pi-Electron theory of transverse optical excitons in semiconducting single-walled carbon nanotubes

TL;DR

This paper develops a quantitative pi-electron based theory explaining transverse optical excitons in semiconducting single-walled carbon nanotubes, highlighting exciton blueshift and interaction effects, with results matching experiments.

Contribution

It introduces a novel pi-electron theory for transverse excitons in nanotubes, explaining blueshift and oscillator strength reduction due to electron-electron interactions.

Findings

Transverse excitons are strongly blueshifted relative to longitudinal ones.

Electron-electron interactions reduce the oscillator strength of transverse absorption.

Theoretical results agree well with experimental data in four nanotubes.

Abstract

We present a quantitative theory of optical absorption polarized transverse to the tube axes in semiconducting single-walled carbon nanotubes. Transverse optical absorption in semiconducting single-walled carbon nanotubes is to an exciton state that is strongly blueshifted, relative to the two lowest longitudinal excitons, by electron-electron interactions. The binding energy of the transverse exciton is considerably smaller than those of the longitudinal excitons. Electron-electron interactions also reduce the relative oscillator strength of the transverse optical absorption. Our theoretical results are in excellent agreement with recent experimental measurements in four chiral nanotubes.