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Landau Velocity for Collective Quantum Hall Breakdown in Bilayer Graphene
1Laboratoire Pierre Aigrain, Ecole Normale Supérieure, PSL University, Sorbonne Université, Université Paris Diderot, Sorbonne Paris Cité, CNRS, 24 rue Lhomond, 75005 Paris, France.
Physical Review Letters
|October 13, 2018
Summary
The quantum Hall effect (QHE) breakdown is observed in bilayer graphene, limited by electron interactions and collective excitations, not just the Zener field. This breakdown precedes an electric-field induced QHE-metal transition.
Area of Science:
- Condensed Matter Physics
- Quantum Phenomena
Background:
- Quantum Hall effect (QHE) breakdown is typically linked to the Zener field.
- Achieving the intrinsic Zener limit in semiconducting heterostructures has been challenging.
Purpose of the Study:
- To report the intrinsic Zener limit of QHE breakdown.
- To investigate the role of collective excitations and electron-electron interactions in QHE breakdown.
Main Methods:
- Utilized high-mobility bilayer graphene.
- Employed high-frequency current noise measurements.
- Analyzed inter-Landau-level (LL) scattering and collective excitations.
Main Results:
- Observed QHE breakdown limited by collective excitations, not solely the Zener field.
- Detected super-Poissonian shot noise indicating inter-LL scattering.
- Identified breakdown as a precursor to an electric-field induced QHE-metal transition.
Conclusions:
- Electron-electron interactions and collective excitations are crucial for QHE breakdown.
- The breakdown mechanism resembles the roton mechanism in superfluids.
- QHE breakdown can transition into an electric-field induced metallic state.
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