Valley Subband Splitting in Bilayer Graphene Quantum Point Contacts

2018/09/17 by R. Kraft, Rainer Kraft, I. V. Krainov +8
Chemistry · Computer Science · Materials Science · Physics and Astronomy · #Bilayer #Bilayer graphene #Chemistry #Condensed matter physics #Conductance #Coulomb #Degeneracy (biology) #Electron #Geometry #Graphene #Graphene research and applications #Membrane #Perpendicular #Physics #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum mechanics #cond-mat.mes-hall

paper · pdf · doi:10.1103/physrevlett.121.257703

published as Phys. Rev. Lett. 121, 257703 (2018)

arxiv created 2018/09/17 · openalex publication_date 2018/12/20 · arxiv updated 2018/12/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We report a study of one-dimensional subband splitting in a bilayer graphene quantum point contact in which quantized conductance in steps of 4e²/h is clearly defined down to the lowest subband. While our source-drain bias spectroscopy measurements reveal an unconventional confinement, we observe a full lifting of the valley degeneracy at high magnetic fields perpendicular to the bilayer graphene plane for the first two lowest subbands where confinement and Coulomb interactions are the strongest and a peculiar merging or mixing of K and K^' valleys from two nonadjacent subbands with indices (N,N+2), which are well described by our semiphenomenological model.

Citations

• Valley splitting in a Si/SiGe quantum point contact
• Gate-induced insulating state in bilayer graphene devices
• An electronic Mach–Zehnder interferometer
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• Aharonov-Bohm effect and broken valley degeneracy in graphene rings
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