title: Band structure asymmetry of bilayer graphene revealed by infrared spectroscopy.
abstract: We report on infrared spectroscopy of bilayer graphene integrated in gated structures. We observe a significant asymmetry in the optical conductivity upon electrostatic doping of electrons and holes. We show that this finding arises from a marked asymmetry between the valence and conduction bands, which is mainly due to the inequivalence of the two sublattices within the graphene layer and the next-nearest-neighbor interlayer coupling. From the conductivity data, the energy difference of the two sublattices and the interlayer coupling energy are directly determined.
authors.affiliation: Department of Physics, University of California, San Diego, La Jolla, California 92093, USA. zhiqiang@physics.ucsd.edu
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Li
authors.forename: E A
authors.initials: EA
authors.lastname: Henriksen
authors.forename: Z
authors.initials: Z
authors.lastname: Jiang
authors.forename: Z
authors.initials: Z
authors.lastname: Hao
authors.forename: M C
authors.initials: MC
authors.lastname: Martin
authors.forename: P
authors.initials: P
authors.lastname: Kim
authors.forename: H L
authors.initials: HL
authors.lastname: Stormer
authors.forename: D N
authors.initials: DN
authors.lastname: Basov