Year: 2006
Type: article
Abstract: We show that the optical absorption spectra of boron nitride (BN) nanotubes are dominated by strongly bound excitons. Our first-principles calculations indicate that the binding energy for the first and dominant excitonic peak depends sensitively on the dimensionality of the system, varying from 0.7 eV in bulk hexagonal BN via 2.1 eV in the single sheet of BN to more than 3 eV in the hypothetical (2, 2) tube. The strongly localized nature of this exciton dictates the fast convergence of its binding energy with increasing tube diameter towards the sheet value. The absolute position of the first excitonic peak is almost independent of the tube radius and system dimensionality. This provides an explanation for the observed "optical gap" constancy for different tubes and bulk hexagonal BN.
Source: Physical Review Letters
Authors: Ludger Wirtz, Andrea Marini, Angel Rubio
Institutions: Centre National de la Recherche Scientifique, Institut d'Electronique, de Microélectronique et de Nanotechnologie, European Theoretical Spectroscopy Facility, University of Rome Tor Vergata, Istituto Nazionale per la Fisica della Materia, University of the Basque Country, Donostia International Physics Center, Freie Universität Berlin
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2163078935