title: Fabry-Pérot interference in gapped bilayer graphene with broken anti-Klein tunneling.
abstract: We report the experimental observation of Fabry-Pérot interference in the conductance of a gate-defined cavity in a dual-gated bilayer graphene device. The high quality of the bilayer graphene flake, combined with the device's electrical robustness provided by the encapsulation between two hexagonal boron nitride layers, allows us to observe ballistic phase-coherent transport through a 1-μm-long cavity. We confirm the origin of the observed interference pattern by comparing to tight-binding calculations accounting for the gate-tunable band gap. The good agreement between experiment and theory, free of tuning parameters, further verifies that a gap opens in our device. The gap is shown to destroy the perfect reflection for electrons traversing the barrier with normal incidence (anti-Klein tunneling). The broken anti-Klein tunneling implies that the Berry phase, which is found to vary with the gate voltages, is always involved in the Fabry-Pérot oscillations regardless of the magnetic field, in sharp contrast with single-layer graphene.
authors.affiliation: Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Varlet
authors.affiliation: Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors.forename: Ming-Hao
authors.initials: MH
authors.lastname: Liu
authors.affiliation: Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors.forename: Viktor
authors.initials: V
authors.lastname: Krueckl
authors.affiliation: Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Dominik
authors.initials: D
authors.lastname: Bischoff
authors.affiliation: Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Pauline
authors.initials: P
authors.lastname: Simonet
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Richter
authors.affiliation: Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Klaus
authors.initials: K
authors.lastname: Ensslin
authors.affiliation: Solid State Physics Laboratory, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ihn