Excitonic Effects on the Optical Response of Graphene and Bilayer Graphene
Abstract
We present first-principles calculations of many-electron effects on the optical response of graphene, bilayer graphene, and graphite employing the GW-Bethe Salpeter equation approach. We find that resonant excitons are formed in these two-dimensional semimetals. The resonant excitons give rise to a prominent peak in the absorption spectrum near 4.5 eV with a different line shape and significantly redshifted peak position from those of an absorption peak arising from interband transitions in an independent quasiparticle picture. In the infrared regime, our calculated optical absorbance per graphene layer is approximately a constant, 2.4%, in agreement with recent experiments; additional low frequency features are found for bilayer graphene because of band structure effects.
- Publication:
-
Physical Review Letters
- Pub Date:
- October 2009
- DOI:
- 10.1103/PhysRevLett.103.186802
- arXiv:
- arXiv:0906.0969
- Bibcode:
- 2009PhRvL.103r6802Y
- Keywords:
-
- 73.22.-f;
- 72.80.Rj;
- 75.70.Ak;
- Electronic structure of nanoscale materials: clusters nanoparticles nanotubes and nanocrystals;
- Fullerenes and related materials;
- Magnetic properties of monolayers and thin films;
- Condensed Matter - Materials Science
- E-Print:
- Phys. Rev. Lett. 103, 186802 (2009)