Berlin 2018 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 20: Focussed Session: Geometry- and Topology-Controlled Nanoarchitectures II
HL 20.6: Talk
Tuesday, March 13, 2018, 15:30–15:45, EW 015
Manipulating quantum Hall edge channels through Scanning Gate Microscopy — Lennart Bours1, Stefano Guiducci1, Alina Mrenca–Kolasinska2, Bartłomiej Szafran2, Jan C. Maan3, and •Stefan Heun1 — 1NEST, Istituto Nanoscienze–CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy — 2AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30–059 Kraków, Poland — 3Radboud University Nijmegen, High Field Magnet Laboratory, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands
We show evidence of the backscattering of quantum Hall edge channels in a narrow graphene Hall bar, induced by the gating effect of the conducting tip of a Scanning Gate Microscope, which we can position with nanometer precision. We show full control over the edge channels and are able, due to the spatial variation of the tip potential, to separate co-propagating edge channels in the Hall bar, creating junctions between regions of different charge carrier density, that have not been observed in devices based on top– or split–gates. The solution of the corresponding quantum scattering problem is presented to substantiate these results, and possible follow–up experiments are discussed.