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Gate-tunable transmission of quantum Hall edge channels in graphene quantum point contact

Research paper by Katrin Zimmermann, Anna Jordan, Frédéric Gay, Kenji Watanabe, Takashi Taniguchi, Zheng Han, Vincent Bouchiat, Hermann Sellier, Benjamin Sacépé

Indexed on: 08 Jun '16Published on: 08 Jun '16Published in: Physics - Mesoscopic Systems and Quantum Hall Effect



Abstract

Charge carriers in the quantum Hall regime propagate via one-dimensional conducting channels that form along the edge of a two-dimensional electron gas. Controlling their transmission through a gate-tunable constriction that spatially confines electron transport is key for many coherent transport experiments. However, in graphene, tailoring constrictions with electrostatic gates remains challenging due to the formation of p-n junctions below gate electrodes along which electron and hole edge channels co-propagate and mix. Here we report the demonstration of confinement and gate-tunable transmission of quantum Hall edge channels in a split-gate defined quantum point contact in high mobility graphene. We identify the exact gate configurations necessary for quantum point contact operation without electron-hole mixing, and for realizing full channel pinch-off. Our work opens the door to a wealth of electron quantum optics experiments in the quantum Hall regime of graphene.