Electrostatically induced quantum point contact in bilayer graphene

Abstract

We report the fabrication of electrostatically defined nanostructures in encapsulated bilayer graphene, with leakage resistances below depletion gates as high as $R\sim 10$G$\Omega$. This exceeds previously reported values of $R=$10 - 100 k$\Omega$.\cite{Zou2010,Yan2010,Zhu2016a} We attribute this improvement to the use of a graphite back gate. We realize two split gate devices which define an electronic channel on the scale of the Fermi-wavelength. A channel gate covering the gap between the split gates varies the charge carrier density in the channel. We observe device-dependent conductance quantization of $\Delta G=2e^2/h$ and $\Delta G=4e^2/h$. In quantizing magnetic fields normal to the sample plane, we recover the four- fold Landau level degeneracy of bilayer graphene. Unexpected mode crossings appear at the crossover between zero magnetic field and the quantum Hall regime.

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Cited by in corpus (72)

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• Single-electron double quantum dots in bilayer graphene
• The Electronic Thickness of Graphene
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• Topologically non-trivial valley states in bilayer graphene quantum point contacts
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• Gate-Controlled Quantum Dots Based on Two-Dimensional Materials
• Electrically inert h-BN/bilayer graphene interface in all-2D-heterostructure FETs
• Shell Filling and Trigonal Warping in Graphene Quantum Dots
• Coherent Jetting behind a gate-defined Channel in Bilayer Graphene
• Fractional quantum Hall effect in CVD-grown graphene
• Anyon braiding and telegraph noise in a graphene interferometer
• Universal chiral Luttinger liquid behavior in a graphene fractional quantum Hall point contact
• Co-existence of classical snake states and Aharanov-Bohm oscillations along graphene p-n junctions
• Pulsed-gate spectroscopy of single-electron spin states in bilayer graphene quantum dots
• Fully automated identification of 2D material samples
• Quantum nanoconstrictions fabricated by cryo-etching in encapsulated graphene
• Theory of tunneling spectra for a few-electron bilayer graphene quantum dot
• Mechanically-reconfigurable van der Waals devices via low-friction gold sliding
• Imaging bulk and edge transport near the Dirac point in graphene moiré superlattices
• Dispersive sensing of charge states in a bilayer graphene quantum dot
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• Electron collimation at van der Waals domain walls in bilayer graphene
• Low Magnetic Field Regime of a Gate-Defined Constriction in High-Mobility Graphene
• Non-Destructive Low-Temperature Contacts to MoS2 Nanoribbon and Nanotube Quantum Dots
• Energy Stability of Branching in the Scanning Gate Response of Two-Dimensional Electron Gases with Smooth Disorder
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• Electrostatic detection of Shubnikov-de-Haas oscillations in bilayer graphene by Coulomb resonances in gate-defined quantum dots
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• Extended Hubbard model describing small multi-dot arrays in bilayer graphene
• Scanning Gate Microscopy of Localized States in a gate-defined Bilayer Graphene Channel
• Selective Etching of Hexagonal Boron Nitride by High-Pressure CF4 Plasma for Individual One-dimensional Ohmic Contacts to Graphene Layers
• Built-in Bernal gap in large-angle-twisted monolayer-bilayer graphene
• Gate-defined superconducting channel in magic-angle twisted bilayer graphene
• Design of graphene waveguide: Effect of edge orientation and waveguide configuration
• Semimetallic features in quantum transport through a gate-defined point contact in bilayer graphene
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• Three-carrier spin blockade and coupling in bilayer graphene double quantum dots
• Tunable spin-orbit splitting in bilayer graphene/WSe${}_2$ quantum devices
• Manipulating electron waves in graphene using carbon nanotube gating
• Tuning confined states and valley g-factors by quantum dot design in bilayer graphene
• Novel circuit design for high-impedance and non-local electrical measurements of two-dimensional materials
• Theory of field-modulated spin-valley-orbital pseudospin physics
• Probing valley phenomena with gate-defined valley splitters
• Four-band effective square lattice model for Bernal-stacked bilayer graphene
• Enhancement in tunneling density of states in Luttinger liquid -- role of non-local interaction
• Electronic and Spin-Orbit Properties of hBN Encapsulated Bilayer Graphene
• Spin polarised quantised transport via one-dimensional nanowire-graphene contacts
• Impact of vacancies on twisted bilayer graphene quantum point contacts
• Hexagonal boron nitride/bilayer graphene moiré superlattices in the Dirac-material family: energy-band engineering and carrier doping by dual gating
• Radio-frequency charge detection on graphene electron-hole double quantum dots