title: Gate-Tunable Landau Level Filling and Spectroscopy in Coupled Massive and Massless Electron Systems.
abstract: We report transport studies on coupled massive and massless electron systems, realized using twisted monolayer-graphene-natural bilayer-graphene stacks. We incorporate the layers in a dual-gated transistor geometry enabling independently tuning their charge density and the perpendicular electric field. In a perpendicular magnetic field, we observe a distinct pattern of gate-tunable Landau level crossings. Screening and interlayer electron-electron interactions yield a nonlinear monolayer gate capacitance. Data analysis enables determination of the monolayer's Fermi velocity and the bilayer's effective mass. The mass obtained is larger than that expected for isolated bilayers, suggesting that the interlayer interactions renormalize the band structure.
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, California 92521, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Cheng
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, California 92521, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, California 92521, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, California 92521, USA.
authors.forename: Cheng
authors.initials: C
authors.lastname: Pan
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Department of Physics and Astronomy, University of California, Riverside, California 92521, USA.
authors.forename: M
authors.initials: M
authors.lastname: Bockrath