Electrostatically Induced Quantum Point Contacts in Bilayer Graphene.
basic_science · Level V
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- Record sourced from PubMed, PMID 29286668.
- Also identified by DOI 10.1021/acs.nanolett.7b04666.
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Abstract
We report the fabrication of electrostatically defined nanostructures in encapsulated bilayer graphene, with leakage resistances below depletion gates as high as R ∼ 10 GΩ. This exceeds previously reported values of R = 10-100 kΩ.1-3 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 ΔG = 2e<sup>2</sup>/h and ΔG = 4e<sup>2</sup>/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.