Magnetic Edge-State Excitons in Zigzag Graphene Nanoribbons
Abstract
We present first-principles calculations of the optical properties of zigzag-edged graphene nanoribbons (ZGNRs) employing the GW-Bethe-Salpeter equation approach with the spin interaction included. Optical response of the ZGNRs is found to be dominated by magnetic edge-state-derived excitons with large binding energy. The absorption spectrum is composed of a characteristic series of exciton states, providing a possible signature for identifying the ZGNRs. The edge-state excitons are charge-transfer excitations with the excited electron and hole located on opposite edges; they moreover induce a spin transfer across the ribbon, resulting in a photoreduction of the magnetic ordering. These novel characteristics are potentially useful in the applications.
- Publication:
-
Physical Review Letters
- Pub Date:
- October 2008
- DOI:
- 10.1103/PhysRevLett.101.186401
- Bibcode:
- 2008PhRvL.101r6401Y
- Keywords:
-
- 71.35.-y;
- 72.80.Rj;
- 73.22.-f;
- 75.70.Ak;
- Excitons and related phenomena;
- Fullerenes and related materials;
- Electronic structure of nanoscale materials: clusters nanoparticles nanotubes and nanocrystals;
- Magnetic properties of monolayers and thin films