Abstract
Low-energy electronic structure of (unbiased and undoped) bilayer graphene consists of two Fermi points with quadratic dispersions if trigonal warping is ignored. We show that short-range (or screened Coulomb) interactions are marginally relevant and use renormalization group to study their effects on low-energy properties of the system. We find that the two quadratic Fermi points spontaneously split into four Dirac points. This results in a nematic state that spontaneously breaks the sixfold lattice rotation symmetry (combined with layer permutation) down to a twofold one, with a finite transition temperature. Critical properties of the transition and effects of trigonal warping are also discussed.
- Received 18 June 2009
DOI:https://doi.org/10.1103/PhysRevB.81.041401
©2010 American Physical Society
Viewpoint
Peeling back the layers or doubling the stakes?
Published 4 January 2010
Calculations of bilayer graphene reveal the possibility of new electronic phases.
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