10.1021/acs.nanolett.7b04666.s001
Hiske Overweg
Hiske
Overweg
Hannah Eggimann
Hannah
Eggimann
Xi Chen
Xi
Chen
Sergey Slizovskiy
Sergey
Slizovskiy
Marius Eich
Marius
Eich
Riccardo Pisoni
Riccardo
Pisoni
Yongjin Lee
Yongjin
Lee
Peter Rickhaus
Peter
Rickhaus
Kenji Watanabe
Kenji
Watanabe
Takashi Taniguchi
Takashi
Taniguchi
Vladimir Fal’ko
Vladimir
Fal’ko
Thomas Ihn
Thomas
Ihn
Klaus Ensslin
Klaus
Ensslin
Electrostatically
Induced Quantum Point Contacts in
Bilayer Graphene
American Chemical Society
2017
Δ G
Ω.
charge carrier density
device-dependent conductance quantization
Unexpected mode crossings
split gate devices
encapsulated bilayer graphene
Electrostatically Induced Quantum Point Contacts
quantum Hall regime
Landau level degeneracy
2017-12-29 16:13:44
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Electrostatically_Induced_Quantum_Point_Contacts_in_Bilayer_Graphene/5743599
We
report the fabrication of electrostatically defined nanostructures
in encapsulated bilayer graphene, with leakage resistances below depletion
gates as high as <i>R</i> ∼ 10 GΩ. This exceeds
previously reported values of <i>R</i> = 10–100 kΩ.− 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 Δ<i>G</i> = 2<i>e</i><sup>2</sup>/<i>h</i> and
Δ<i>G</i> = 4<i>e</i><sup>2</sup>/<i>h</i>. 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.