Dresden 2017 – scientific programme

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O: Fachverband Oberflächenphysik

O 32: Focus Session: Charge Transport at Surfaces and Nanostructures with Multi-probe Techniques I

O 32.3: Talk

Tuesday, March 21, 2017, 11:15–11:30, WIL C307

Electrical resistance of individual defects at a topological insulator surface — •Felix Lüpke, Markus Eschbach, Tristan Heider, Martin Lanius, Peter Schüffelgen, Daniel Rosenbach, Nils von den Driesch, Vasily Cherepanov, Gregor Mussler, Lukasz Plucinski, Detlev Grützmacher, Claus M. Schneider, and Bert Voigtländer — Peter Grünberg Institute and JARA-FIT, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany

We determine the resistance of different kinds of defects at the surface of a (Bi_0.53Sb_0.47)₂Te₃ topological insulator thin film by scanning tunneling potentiometry. The largest localized voltage drop we find to be located at domain boundaries in the topological insulator film, with a resistivity about four times higher than that of a step edge. Furthermore, we resolve resistivity dipoles located around voids in the sample surface. The influence of such defects with a typical diameter of 5 nm on the resistance of the topological insulator is analyzed by means of a resistor network model. Here, we show that local changes in the conductivity, e.g. due to the voids in the surface, give rise to a persistent voltage drop across the sample far away from the actual position of the defect.