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arXiv · 1805.05770

Landau velocity for collective quantum Hall breakdown in bilayer graphene

W. Yang·H. Graef·X. Lu·G. Zhang·T. Taniguchi·K. Watanabe·A. Bachtold·E. H. T. Teo·E. Baudin·E. Bocquillon·G. Fève·J-M. Berroir·D. Carpentier·M. O. Goerbig·B. Plaçais
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Abstract

Breakdown of the quantum Hall effect (QHE) is commonly associated with an electric field approaching the inter Landau-level (LL) Zener field, ratio of the Landau gap and cyclotron radius. Eluded in semiconducting heterostructures, in spite of extensive investigation, the intrinsic Zener limit is reported here using high-mobility bilayer graphene and high-frequency current noise. We show that collective excitations arising from electron-electron interactions are essential. Beyond a noiseless ballistic QHE regime a large superpoissonian shot noise signals the breakdown via inter-LL scattering. The breakdown is ultimately limited by collective excitations in a regime where phonon and impurity scattering are quenched. The breakdown mechanism can be described by a Landau critical velocity as it bears strong similarities with the roton mechanism of superfluids.

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W. Yang, H. Graef, X. Lu, G. Zhang, T. Taniguchi, K. Watanabe, A. Bachtold, E. H. T. Teo, E. Baudin, E. Bocquillon, G. Fève, J-M. Berroir, D. Carpentier, M. O. Goerbig, B. Plaçais. 2018-05-15. Landau velocity for collective quantum Hall breakdown in bilayer graphene. https://doi.org/10.1103/physrevlett.121.136804

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