title: Energy Gaps and Layer Polarization of Integer and Fractional Quantum Hall States in Bilayer Graphene.
abstract: Owing to the spin, valley, and orbital symmetries, the lowest Landau level in bilayer graphene exhibits multicomponent quantum Hall ferromagnetism. Using transport spectroscopy, we investigate the energy gaps of integer and fractional quantum Hall (QH) states in bilayer graphene with controlled layer polarization. The state at filling factor ν=1 has two distinct phases: a layer polarized state that has a larger energy gap and is stabilized by high electric field, and a hitherto unobserved interlayer coherent state with a smaller gap that is stabilized by large magnetic field. In contrast, the ν=2/3 quantum Hall state and a feature at ν=1/2 are only resolved at finite electric field and large magnetic field. These results underscore the importance of controlling layer polarization in understanding the competing symmetries in the unusual QH system of BLG.
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, Riverside, California 91765, USA.
authors.forename: Yanmeng
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, Riverside, California 91765, USA.
authors.forename: Yongjin
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, Riverside, California 91765, USA.
authors.forename: Shi
authors.initials: S
authors.lastname: Che
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, Riverside, California 91765, USA.
authors.forename: Ziqi
authors.initials: Z
authors.lastname: Pi
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, Riverside, California 91765, USA.
authors.forename: Timothy
authors.initials: T
authors.lastname: Espiritu
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, Riverside, California 91765, USA.
authors.forename: Petr
authors.initials: P
authors.lastname: Stepanov
authors.affiliation: National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Smirnov
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, Riverside, California 91765, USA.
authors.forename: Chun Ning
authors.initials: CN
authors.lastname: Lau
authors.affiliation: Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, USA.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang