Justin C. W. Song, Andrey V. Shytov, Leonid S. Levitov
We show that coupling of Dirac particles in graphene to moir\'e superlattice potential in G/hBN heterostructures is strongly affected by interactions. Interacting Dirac particles respond strongly to a pseudospin-dependent (`colored') potential arising due to the A-B sublattice modulation and relatively more weakly to a scalar potential which is sublattice-blind. As a result, the effective potential seen by electrons in graphene becomes predominantly `colored,' leading to pseudospin-dependent Bragg scattering. Many-body effects generate giant enhancement of the gap at the Dirac point, which can overtake the enhancement of the minigaps opened by Bragg scattering at the superlattice Brillouin zone edges. We predict a power-law dependence for the gap vs. moir\'e pattern wavelength, which can be used to directly test the effects of interactions in experiment.
View original:
http://arxiv.org/abs/1212.6759
No comments:
Post a Comment