title: Fractional Quantum Hall States in Bilayer Graphene Probed by Transconductance Fluctuations.
abstract: We have investigated fractional quantum Hall (QH) states in Bernal-stacked bilayer graphene using transconductance fluctuation measurements. A variety of odd-denominator fractional QH states with νQH → νQH + 2 symmetry, as previously reported, are observed. However, surprising is that also particle-hole symmetric states are clearly resolved in the same measurement set. We attribute their emergence to the reversal of orbital states in the octet level scheme induced by a strong local charge imbalance, which can be captured by the transconductance fluctuations. Also the even-denominator fractional QH state at filling -1/2 is observed. However, contrary to a previous study on a suspended graphene layer [ Ki et al. Nano Lett. 2014, 14 , 2135 ], the particle-hole symmetric state at filling 1/2 is detected as well. These observations suggest that the stability of both odd and even denominator fractional QH states is very sensitive to local transverse electric fields in bilayer graphene.
authors.affiliation: Department of Physics, Pohang University of Science and Technology , Pohang 790-784, Korea.|Max-Planck-Institut für Festköperforschung , 70569 Stuttgart, Germany.
authors.forename: Youngwook
authors.initials: Y
authors.lastname: Kim
authors.affiliation: KIST Jeonbuk Institute of Advanced Composite Materials , Jeonbuk 565-905, Korea.
authors.forename: Dong Su
authors.initials: DS
authors.lastname: Lee
authors.affiliation: Center for Quantum Measurement Science, Korea Research Institute of Standards and Science , Daejeon, 305-340, Korea.
authors.forename: Suyong
authors.initials: S
authors.lastname: Jung
authors.affiliation: Faculty of Physics, University of Vienna , Boltzmanngasse 5, 1090 Vienna, Austria.|STU Center for Nanodiagnostics , Vazovova 5, 812 43 Bratislava, Slovakia.
authors.forename: Viera
authors.initials: V
authors.lastname: Skákalová
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science , 1-1 Namiki, Tsukuba, 305-0044, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science , 1-1 Namiki, Tsukuba, 305-0044, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Department of Physics, Pohang University of Science and Technology , Pohang 790-784, Korea.
authors.forename: Jun Sung
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Max-Planck-Institut für Festköperforschung , 70569 Stuttgart, Germany.
authors.forename: Jurgen H
authors.initials: JH
authors.lastname: Smet
keywords: Bilayer graphene; electron−hole symmetry; fractional quantum Hall states; transconductance fluctuations