title: Bilayer graphene. Chemical potential and quantum Hall ferromagnetism in bilayer graphene.
abstract: Bilayer graphene has a distinctive electronic structure influenced by a complex interplay between various degrees of freedom. We probed its chemical potential using double bilayer graphene heterostructures, separated by a hexagonal boron nitride dielectric. The chemical potential has a nonlinear carrier density dependence and bears signatures of electron-electron interactions. The data allowed a direct measurement of the electric field-induced bandgap at zero magnetic field, the orbital Landau level (LL) energies, and the broken-symmetry quantum Hall state gaps at high magnetic fields. We observe spin-to-valley polarized transitions for all half-filled LLs, as well as emerging phases at filling factors ν = 0 and ν = ±2. Furthermore, the data reveal interaction-driven negative compressibility and electron-hole asymmetry in N = 0, 1 LLs.
authors.affiliation: Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Road, Austin, TX 78758, USA.
authors.forename: Kayoung
authors.initials: K
authors.lastname: Lee
authors.affiliation: Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Road, Austin, TX 78758, USA.
authors.forename: Babak
authors.initials: B
authors.lastname: Fallahazad
authors.affiliation: Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Road, Austin, TX 78758, USA.
authors.forename: Jiamin
authors.initials: J
authors.lastname: Xue
authors.affiliation: Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Road, Austin, TX 78758, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Dillen
authors.affiliation: Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Road, Austin, TX 78758, USA.
authors.forename: Kyounghwan
authors.initials: K
authors.lastname: Kim
authors.affiliation: National Institute for Materials Science, 1-1 Namiki Tsukuba Ibaraki 305-0044, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: National Institute for Materials Science, 1-1 Namiki Tsukuba Ibaraki 305-0044, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Road, Austin, TX 78758, USA. etutuc@mer.utexas.edu.
authors.forename: Emanuel
authors.initials: E
authors.lastname: Tutuc