Excitonic Effects and Optical Spectra of Single-Walled Carbon Nanotubes

TL;DR

This paper investigates how many-electron interactions, specifically excitonic effects, significantly influence the optical spectra of small-diameter single-walled carbon nanotubes, clarifying previous experimental and theoretical discrepancies.

Contribution

It provides first-principles calculations of electron-hole interactions in carbon nanotubes, revealing large excitonic effects on their optical properties.

Findings

Excitons are bound by ~1 eV in semiconducting nanotubes.

Excitons are bound by ~100 meV in metallic nanotubes.

Many-electron effects explain previous theory-experiment discrepancies.

Abstract

Many-electron effects often dramatically modify the properties of reduced dimensional systems. We report calculations, based on an many-electron Green's function approach, of electron-hole interaction effects on the optical spectra of small-diameter single-walled carbon nanotubes. Excitonic effects qualitatively alter the optical spectra of both semiconducting and metallic tubes. Excitons are bound by ~ 1 eV in the semiconducting (8,0) tube and by ~ 100 meV in the metallic (3,3) tube. These large many-electron effects explain the discrepancies between previous theories and experiments.