Fabry-Pérot interference in gapped bilayer graphene with broken anti-Klein tunneling

Abstract

We report the experimental observation of Fabry-Pérot (FP) interference in the conductance of a gate-defined cavity in a dual-gated bilayer graphene (BLG) device. The high quality of the BLG 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 bandgap. 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 FP oscillations regardless of the magnetic field, in sharp contrast with single-layer graphene.

5 pages, 4 figures

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• Boron nitride substrates for high-quality graphene electronics
• Chiral tunneling and the Klein paradox in graphene
• Biased bilayer graphene: semiconductor with a gap tunable by electric field effect
• Gate-induced insulating state in bilayer graphene devices
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• Quantum interference and Klein tunneling in graphene heterojunctions
• The electronic properties of bilayer graphene
• Selective transmission of Dirac electrons and ballistic magnetoresistance of \textit{n-p} junctions in graphene
• Klein Backscattering and Fabry-Perot Interference in Graphene Heterojunctions
• Electronic Transport in Dual-gated Bilayer Graphene at Large Displacement Fields
• Atomic collapse, Lorentz boosts, Klein scattering, and other quantum-relativistic phenomena in graphene
• Efficient quantum transport simulation for bulk graphene heterojunctions

Cited by in corpus (7)

• Creating and Probing Electron Whispering Gallery Modes in Graphene
• An On/Off Berry Phase Switch in Circular Graphene Resonators
• Fabry-Pérot resonances in a graphene/hBN Moiré superlattice
• Giant valley-isospin conductance oscillations in ballistic graphene
• Evidence of electronic cloaking from chiral electron transport in bilayer graphene nanostructures
• Photon-assisted transport in bilayer graphene flakes
• Intervalley quantum interference and measurement of Berry phase in bilayer graphene