Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 63: Focus Session: Charge Transport at Surfaces and Nanostructures with Multi-probe Techniques

O 63.4: Poster

Dienstag, 21. März 2017, 18:30–20:30, P2-OG3

Disentangling in situ top and bottom conductance of a topological insulator thin film — •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

Charge transport in thin films of 3D topological insulator materials can be through the top and the bottom topological surface state as well as through the interior of the film. The latter undesirable conductivity can be minimized by the use of thin films (10 nm) and the use of MBE grown ternary material systems with reduced bulk conductivity. However, it is still difficult to separate the contributions of the three channels to the conduction. Using a multi-tip STM we performed in situ gate-dependent four-probe conductivity measurements of (Bi_0.53Sb_0.47)₂Te₃ thin films. Combining the information from these measurements with the band structure obtained from subsequent ARPES measurements, we determine the carrier densities as well as the mobilities in the top and bottom topological surface state channels.