Bulletin of the American Physical Society
APS March Meeting 2011
Volume 56, Number 1
Monday–Friday, March 21–25, 2011; Dallas, Texas
Session A2: Compressibility and Transport in Bilayer Graphene
8:00 AM–11:00 AM,
Monday, March 21, 2011
Room: Ballroom A2
Sponsoring Unit: DCMP
Chair: Sankar Das Sarma, University of Maryland
Abstract ID: BAPS.2011.MAR.A2.5
Abstract: A2.00005 : Local Compressibility Measurements of Correlated States in Suspended Bilayer Graphene*
10:24 AM–11:00 AM
Preview Abstract Abstract
Bilayer graphene has attracted considerable interest due to the important role played by many-body effects, particularly at low energies. The exceptional quality of suspended devices has enabled the observation of interaction-driven broken-symmetry states and the fractional quantum Hall effect. Here we report local compressibility measurements of a suspended graphene bilayer. We find that the energy gaps at filling factors +/- 4 do not vanish at low fields, but instead merge into an incompressible region near the charge neutrality point at zero electric and magnetic field. These results indicate the existence of a zero-field ordered state and are consistent with the formation of either an anomalous quantum Hall state or a nematic phase with broken rotational symmetry. At higher fields, we measure the intrinsic energy gaps of broken-symmetry states at filling factor 0, +/- 1 and +/-2, and find that they scale linearly with magnetic field, yet another manifestation of the strong Coulomb interactions in bilayers.
*U.S. DoE \#DE-SC0001819, U.S. ONR MURI on Graphene, NSF PHY-0646094, the Alexander von Humbolt Foundation, CNS: NSF \# ECS-0335765.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.A2.5
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