title: Interaction phenomena in graphene seen through quantum capacitance.
abstract: Capacitance measurements provide a powerful means of probing the density of states. The technique has proved particularly successful in studying 2D electron systems, revealing a number of interesting many-body effects. Here, we use large-area high-quality graphene capacitors to study behavior of the density of states in this material in zero and high magnetic fields. Clear renormalization of the linear spectrum due to electron-electron interactions is observed in zero field. Quantizing fields lead to splitting of the spin- and valley-degenerate Landau levels into quartets separated by interaction-enhanced energy gaps. These many-body states exhibit negative compressibility but the compressibility returns to positive in ultrahigh B. The reentrant behavior is attributed to a competition between field-enhanced interactions and nascent fractional states.
authors: School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United Kingdom.
authors: G L
authors: GL
authors: Yu
authors: R
authors: R
authors: Jalil
authors: Branson
authors: B
authors: Belle
authors: Alexander S
authors: AS
authors: Mayorov
authors: Peter
authors: P
authors: Blake
authors: Frederick
authors: F
authors: Schedin
authors: Sergey V
authors: SV
authors: Morozov
authors: Leonid A
authors: LA
authors: Ponomarenko
authors: F
authors: F
authors: Chiappini
authors: S
authors: S
authors: Wiedmann
authors: Uli
authors: U
authors: Zeitler
authors: Mikhail I
authors: MI
authors: Katsnelson
authors: A K
authors: AK
authors: Geim
authors: Kostya S
authors: KS
authors: Novoselov
authors: Daniel C
authors: DC
authors: Elias
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