Fractional quantum Hall effect and insulating phase of Dirac electrons in graphene

By Xu Du, I. Skachko, F. Duerr, A. Luican, E. Andrei. Nature, 2009

786 citations recorded by the source corpus.

In graphene, which is an atomic layer of crystalline carbon, two of the distinguishing properties of the material are the charge carriers’ two-dimensional and relativistic character. The first experimental evidence of the two-dimensional nature of graphene came from the observation of a sequence of plateaus in measurements of its transport properties in the presence of an applied magnetic field. These are signatures of the so-called integer quantum Hall effect. However, as a consequence of the relativistic character of the charge carriers, the integer quantum Hall effect observed in graphene is qualitatively different from its semiconductor analogue. As a third distinguishing feature of graphene, it has been conjectured that interactions and correlations should be important in this material, but surprisingly, evidence of collective behaviour in graphene is lacking. In particular, the quintessential collective quantum behaviour in two dimensions, the fractional quantum Hall effect (FQHE), has so far resisted observation in graphene despite intense efforts and theoretical predictions of its existence. Here we report the observation of the FQHE in graphene. Our observations are made possible by using suspended graphene devices probed by two-terminal charge transport measurements. This allows us to isolate the sample from substrate-induced perturbations that usually obscure the effects of interactions in this system and to avoid effects of finite geometry. At low carrier density, we find a field-induced transition to an insulator that competes with the FQHE, allowing its observation only in the highest quality samples. We believe that these results will open the door to the physics of FQHE and other collective behaviour in graphene.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/0365d0c2a8e85b9fd85e0b7392b470f298b26fdd

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Citations in the corpus

Universal topological quantum computation from a superconductor/Abelian quantum Hall heterostructure (2013, background): “Quantum Hall states supporting fractionally charged Abelian anyons are, by now, widely believed to surface in a myriad of settings, including GaAs [20], graphene [21,22], oxide interfaces [23,24], and CdTe Published by the American Physical Society under the terms of”
Scanning tunnelling microscopy and spectroscopy of ultra-flat graphene on hexagonal boron nitride. (2011, background): “One possibility to get rid of substrate interactions is to suspend graphene[6, 7], as shown by the drastic improvement in mobility which has enabled the observation of the fractional quantum Hall effect in suspended devices[14, 15].”
Experimental Review of Graphene (2011, background): “The effect is much more robust under increase in temperature than its counterpart in semiconducting devices, revealing the suspected enhancement of electron-electron interactions in graphene compared to those occurring in 2DEGs (Dean et al., 2010a; Du et al., 2009).”
Regenerative oscillation and four-wave mixing in graphene optoelectronics (2012, background): “2104@columbia.edu The unique linear and massless band structure of graphene, in a purely two-dimensional Dirac fermionic structure, have led to intense research spanning from condensed matter physics [1, 2, 3, 4, 5] to nanoscale device applications covering the electrical [6, 7], thermal [8, 9], mec”
Quantum Hall physics : Hierarchies and conformal field theory techniques (2016, background): “, 2010), and particularly graphene (Bolotin et al., 2009; Du et al., 2009; Dean et al., 2011).”
Graphene Photonics and Optoelectroncs (2010, background): “Combining equations (4) and (5) and eliminating N gives:”
Electrical characterization of 2D materials-based field-effect transistors (2020, methodology): “Over the years, techniques such as van der Waals-based assembly [105], full device encapsulation, and clean contact fabrication have enabled the observation of SdH oscillations at moderate magnetic fields (<5 T) from graphene [106, 107] and other 2D semiconductorbased devices [108, 109].”
Production, properties and potential of graphene (2010, background): “[158] Du X, Skachko I, Duerr F, Luican A, Andrei EY.”
Magnetic Catalysis: A Review (2012, background): “It was observed experimentally [186, 120, 37, 22] that there appear additional plateaus in the Hall conductivity when graphene is placed in a very strong magnetic field.”