title: Band structures of bilayer graphene superlattices.
abstract: We formulate a low energy effective Hamiltonian to study superlattices in bilayer graphene (BLG) using a minimal model which supports quadratic band touching points. We show that a one dimensional (1D) periodic modulation of the chemical potential or the electric field perpendicular to the layers leads to the generation of zero-energy anisotropic massless Dirac fermions and finite energy Dirac points with tunable velocities. The electric field superlattice maps onto a coupled chain model comprised of "topological" edge modes. 2D superlattice modulations are shown to lead to gaps on the mini-Brillouin zone boundary but do not, for certain symmetries, gap out the quadratic band touching point. Such potential variations, induced by impurities and rippling in biased BLG, could lead to subgap modes which are argued to be relevant to understanding transport measurements.
authors.affiliation: Department of Physics, University of Toronto, Toronto, Ontario, Canada M5S 1A7.
authors.forename: Matthew
authors.initials: M
authors.lastname: Killi
authors.forename: Si
authors.initials: S
authors.lastname: Wu
authors.forename: Arun
authors.initials: A
authors.lastname: Paramekanti