Anomalous exciton condensation in graphene bilayers.
In ordinary semiconductor bilayers, exciton condensates appear at total Landau-level filling factor nu{T}=1. We predict that similar states will occur in Bernal stacked graphene bilayers at many nonzero integer filling factors. For nu{T}=-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.
Barlas
Yafis
Y
National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, USA.
Côté
R
R
Lambert
J
J
Macdonald
A H
AH