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arXiv · 1009.4669

Quantum Transport and Field Induced Insulating States in Bilayer Graphene pnp Junctions

Lei Jing·Jairo Velasco Jr.·Philip Kratz·Gang Liu·Wenzhong Bao·Marc Bockrath·Chun Ning Lau
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Abstract

We perform transport measurements in high quality bilayer graphene pnp junctions with suspended top gates. At a magnetic field B=0, we demonstrate band gap opening by an applied perpendicular electric field, with an On/Off ratio up to 20,000 at 260mK. Within the band gap, the conductance decreases exponentially by 3 orders of magnitude with increasing electric field, and can be accounted for by variable range hopping with a gate-tunable density of states, effective mass, and localization length. At large B, we observe quantum Hall conductance with fractional values, which arise from equilibration of edge states between differentially-doped regions, and the presence of an insulating state at filling factor ν=0. Our work underscores the importance of bilayer graphene for both fundamental interest and technological applications.

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Lei Jing, Jairo Velasco Jr., Philip Kratz, Gang Liu, Wenzhong Bao, Marc Bockrath, Chun Ning Lau. 2010-09-24. Quantum Transport and Field Induced Insulating States in Bilayer Graphene pnp Junctions. https://doi.org/10.1021/nl101901g

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