Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 14: Graphene
TT 14.10: Vortrag
Montag, 1. April 2019, 17:45–18:00, H22
Valley subband splitting in bilayer graphene quantum point contact — •Rainer Kraft1, Igor V. Krainov2, Vanessa Gall1,3, Alexander P. Dmitriev2, Ralph Krupke1,4, Igor V. Gornyi1,2,3, and Romain Danneau1 — 1Institute of Nanotechnology, Karlsruhe Institute of Technology, D-76021 Karlsruhe, Germany — 2A.F. Ioffe Physico-Technical Institute, 194021 St. Petersburg, Russia — 3Institute for Condensed Matter Theory, Karlsruhe Institute of Technology, D-76128 Karlsruhe, Germany — 4Department of Materials and Earth Sciences, Technical University Darmstadt, Darmstadt, Germany
Here we present a study of the 1D confinement in a bilayer graphene quantum point contact, i.e. a system with fourfold degeneracy (spin and valley). The constriction is designed electrostatically with dual-gated nanostructures in edge-connected bilayer graphene-hexagonal boron nitride van der Waals heterostructures, employing the possibility of local band gap engineering in bilayer graphene. While quantized conductance due to size-quantization is observed in steps of 4 e2/h down to the lowest subband, the valley-degeneracy of the 1D subbands is lifted under a perpendicular magnetic field and a peculiar pattern of splitting and merging from two non-adjacent subbands arises.