Percolation transitions in bilayer graphene encapsulated by hexagonal boron nitride
Abstract
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 κ of the temperature-induced transition broadening, the critical exponent γ of the localization length, and the exponent p ruling the temperature scaling of the coherence length, finding consistency with the relation γ =p /2 κ . The observed value of κ =0.30 (0.28 ,0.32 ) deviates from that of the quantum Hall critical point. The obtained γ =1.25 (0.96 ,1.54 ) questions the validity of a pure Anderson transition, and reveals percolation as the underlying driving mechanism.
- Publication:
-
Physical Review B
- Pub Date:
- October 2014
- DOI:
- 10.1103/PhysRevB.90.161408
- Bibcode:
- 2014PhRvB..90p1408C
- Keywords:
-
- 72.80.Vp;
- 73.43.Qt;
- Magnetoresistance