Percolation transitions in bilayer graphene encapsulated by hexagonal boron nitride

We studied the plateau-plateau transitions that characterize the electrical transport in the quantum Hall regime in a high mobility bilayer graphene flake encapsulated by hexagonal boron nitride at magnetic fields up to 9 T and temperatures above 300 mK. We measured independently the exponent Kappa...

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Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2014-10, Vol.90 (16), Article 161408
Main Authors: Cobaleda, C., Pezzini, S., Rodriguez, A., Diez, E., Bellani, V.
Format: Article
Language:English
Subjects:
Boron nitride
Coherence
Condensed matter
Consistency
Encapsulation
Exponents
Graphene
Magnetic fields
Percolation
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Summary:We studied the plateau-plateau transitions that characterize the electrical transport in the quantum Hall regime in a high mobility bilayer graphene flake encapsulated by hexagonal boron nitride at magnetic fields up to 9 T and temperatures above 300 mK. We measured independently the exponent Kappa of the temperature-induced transition broadening, the critical exponent gamma of the localization length, and the exponent p ruling the temperature scaling of the coherence length, finding consistency with the relation gamma = p/2 Kappa . The observed value of Kappa = 0.30(0.28, 0.32) deviates from that of the quantum Hall critical point. The obtained gamma = 1.25(0.96, 1.54) questions the validity of a pure Anderson transition, and reveals percolation as the underlying driving mechanism.
ISSN:1098-0121
1550-235X
DOI:10.1103/PhysRevB.90.161408