Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 27: Focus Session: Topological Insulators on Coupled Quantum Wells (joint session DS, HL, MA, O, TT, organized by HL)

TT 27.1: Hauptvortrag

Dienstag, 21. März 2017, 09:30–10:00, POT 151

Edge conduction in the 2D topological insulator candidate InAs/GaSb — •Susanne Mueller, Matija Karalic, Christopher Mittag, Lars Tiemann, Thomas Tschirky, Quansheng Wu, Alexey A. Soluyanov, Atin Nath Pal, Christophe Charpentier, Matthias Troyer, Werner Wegscheider, Klaus Ensslin, and Thomas Ihn — Physics Department ETH Zurich, 8093 Zurich, Switzerland

We have studied transport measurements in mesoscopic Hall bars in the electrically tunable double quantum well structure InAs/GaSb. Helical edge states are predicted to dominate transport in the hybridization gap at zero magnetic field. We measure the non-local resistances and find a scaling according to Landauer-Büttikers expectations for helical edge modes [1]. No dependence on edge length could be observed in these devices, despite recent findings of trivial edges in this material system [2, 3]. To deepen the discussion, we are currently investigating the edge length dependence over a broader range of sample sizes and complete the discussion with clear experimental signature for the inverted phase [4] and the effect of strain on the bulk band structure [5], having in mind that an optimized bulk insulator is a necessary starting point for an edge study.

[1] S. Mueller et al., Phys. Rev. B 92, 081303 (2015)

[2] F. Nichele et al., New J. Phys. 18, 083005 (2016)

[3] B.-M. Nguyen et al., Phys. Rev. Lett. 117, 077701 (2016)

[4] M. Karalic, S. Mueller et al., Phys. Rev. B 94, 241402 (2016)

[5] L. Tiemann, S. Mueller et al., arXiv: 1610.06776