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HL: Fachverband Halbleiterphysik

HL 20: Focussed Session: Geometry- and Topology-Controlled Nanoarchitectures II

HL 20.6: Vortrag

Dienstag, 13. März 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.