title: Insulator-quantum Hall transitionin monolayer epitaxial graphene.
abstract: We report on magneto-transport measurements on low-density, large-area monolayer epitaxial graphene devices grown on SiC. We observe temperature (T)-independent crossing points in the longitudinal resistivity ρxx, which are signatures of the insulator-quantum Hall (I-QH) transition, in all three devices. Upon converting the raw data into longitudinal and Hall conductivities σxxand σxy, in the most disordered device, we observedT-driven flow diagram approximated by the semi-circle law as well as theT-independent point inσxyneare2/h. We discuss our experimental results in the context of the evolution of the zero-energy Landau level at low magnetic fieldsB. We also compare the observed strongly insulating behaviour with metallic behaviour and the absence of the I-QH transition in graphene on SiO2prepared by mechanical exfoliation.
authors.affiliation: National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA; Department of Physics, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Lung-I
authors.initials: LI
authors.lastname: Huang
authors.affiliation: National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA; Department of Physics, Georgetown University, Washington, DC 20057, USA.
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Yang
authors.affiliation: National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA.
authors.forename: Randolph E
authors.initials: RE
authors.lastname: Elmquist
authors.affiliation: Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Shun-Tsung
authors.initials: ST
authors.lastname: Lo
authors.affiliation: Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Fan-Hung
authors.initials: FH
authors.lastname: Liu
authors.affiliation: Department of Physics, National Taiwan University, Taipei 106, Taiwan; Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan; Geballe Laboratory for Advanced Materials (GLAM), Stanford University, Stanford, CA 94305, USA.
authors.forename: Chi-Te
authors.initials: CT
authors.lastname: Liang