Freiburg 2019 – scientific programme

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FM: Fall Meeting

FM 64: Poster: Topology

FM 64.6: Poster

Wednesday, September 25, 2019, 16:30–18:30, Tents

Top-down fabrication of gate-tuneable bulk-insulating TI nanowires and their quantum transport — •Matthias Rößler, Dingxun Fan, Felix Münning, Oliver Breunig, Andrea Bliesener, Gertjan Lippertz, Alexey Taskin, and Yoichi Ando — II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany -

With proximity-induced superconductivity, bulk-insulating topological insulator nanowires (TI NWs) are expected to serve as a robust platform for realizing Majorana bound states. When exploiting their non-Abelian exchange statistics, these states could enable topological quantum computation schemes. Compared to previous experiments on semiconductor nanowires, a TI-based platform for MBS is predicted to have relaxed requirements for the tuning of chemical potential and magnetic field, resulting from the inherent property of spin-momentum locking. We have performed fabrication and optimization of TI NWs based on a scalable approach, namely etching of MBE-grown high quality BST thin films. Using this technique, highly gate-tuneable bulk insulating TI NWs with a diameter of less than 100 nm can be prepared to form arbitrary networks. Signatures of a so-called π-shift in Aharonov-Bohm-like transport oscillations indicate an opening and re-closing of the topologically protected 1D zero-gap mode unique to TI NWs with an axial magnetic flux dependent quantized 1D surface sub-band dispersion. Making use of this platform, we present first results on proximity-induced superconductivity in such TI nanowires.