Excitons and Many-Electron Effects in the Optical Response of Single-Walled Boron Nitride Nanotubes

TL;DR

This paper presents first-principles calculations revealing that excitonic effects significantly influence the optical response of single-walled BN nanotubes, with strong electron-hole interactions leading to complex excitonic states and novel optical behaviors.

Contribution

It provides the first detailed theoretical analysis of excitonic effects and electron-hole interactions in BN nanotubes, highlighting their importance over carbon nanotubes.

Findings

Excitonic effects are more significant in BN nanotubes than in carbon nanotubes.

Electron-hole interactions create complex excitonic states with high binding energies.

BN nanotubes exhibit unique optical behaviors due to coherent superpositions of multiple subband transitions.

Abstract

We report first-principles calculations of the effects of quasiparticle self-energy and electron-hole interaction on the optical properties of single-walled BN nanotubes. Excitonic effects are shown to be even more important in BN nanotubes than in carbon nanotubes. Electron-hole interactions give rise to complexes of bright (and dark) excitons, which qualitatively alter the optical response. Excitons with binding energy larger than 2 eV are found in the (8,0) BN nanotubes. Moreover, unlike the carbon nanotubes, theory predicts that these exciton states are comprised of coherent supposition of transitions from several different subband pairs, giving rise to novel behaviors.