Exciton Effects in Optical Absorption Spectra of Boron-Nitride Nanotubes
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- Nanotechnology Res. Inst. AIST
- Document Type:
- Presentation
- Date:
- Received 21 October 2009 00:32 UTC; Posted 26 October 2009
- Subjects:
- Chemistry
- Abstract:
Exciton effects are studied in single-wall boron-nitride (BN) nanotubes. Linear absorption spectra are calculated with changing
the chiral index of the zigzag nanotubes. We consider the extended Hubbard model with atomic energies at the boron and nitrogen sites.
Exciton effects are calculated using the configuration interaction technique. The Coulomb interaction dependence of the band gap,
the lowest exciton energy, and the binding energy of the exciton are discussed. The optical gap of the (5,0) nanotube is about 6 eV
at the onsite interaction U=2t with the hopping integral t=1.1 eV. The binding energy of the exciton is 0.50 eV for these parameters.
This energy agrees well with that of other theoretical investigations. We find that the energy gap and the binding energy are almost
independent of the geometries of the nanotubes. This novel property is in contrast with that of the carbon nanotubes which show metallic
and semiconducting properties depending on the chiral index. Comparison with recent experiments will be discussed.- Presented at:
- ICCMSE 2009, 29 September 2009
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- License:
- This document is licensed to the public under the Creative Commons Attribution 3.0 License
- How to cite this document:
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Harigaya, Kikuo. Exciton Effects in Optical Absorption Spectra of Boron-Nitride Nanotubes. Available from Nature Precedings <http://dx.doi.org/10.1038/npre.2009.3879.1> (2009)
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