Anomalous Exciton Condensation in Graphene Bilayers
Abstract
In ordinary semiconductor bilayers, exciton condensates appear at total Landau-level filling factor νT=1. We predict that similar states will occur in Bernal stacked graphene bilayers at many nonzero integer filling factors. For νT=-3, 1 we find that the superfluid density of the exciton condensate vanishes and that a finite-temperature fluctuation-induced first order isotropic-smectic phase transition occurs when the layer densities are not balanced. These anomalous properties of bilayer graphene exciton condensates are due to the degeneracy of Landau levels with n=0 and n=1 orbital character.
- Publication:
-
Physical Review Letters
- Pub Date:
- March 2010
- DOI:
- 10.1103/PhysRevLett.104.096802
- arXiv:
- arXiv:0909.1502
- Bibcode:
- 2010PhRvL.104i6802B
- Keywords:
-
- 73.43.-f;
- 71.35.Ji;
- 73.21.-b;
- Quantum Hall effects;
- Excitons in magnetic fields;
- magnetoexcitons;
- Electron states and collective excitations in multilayers quantum wells mesoscopic and nanoscale systems;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 4 pages, 1 figure