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HL: Fachverband Halbleiterphysik

HL 80: Quantum transport and quantum Hall effects

HL 80.7: Vortrag

Freitag, 20. März 2020, 11:30–11:45, POT 51

Proximity-Induced Superconductivity in top-down fabricated bulk-insulating TI nanowires — •Matthias Rößler, Dingxun Fan, Junya Feng, Andrea Bliesener, Gertjan Lippertz, Alexey Taskin, and Yoichi Ando — II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany

With proximity-induced superconductivity, bulk-insulating topological insulator nanowires (TINWs) are expected to serve as a robust platform for realizing Majorana bound states (MBSs). Thanks to their predicted non-Abelian exchange statistics, MBSs could enable realizations of topological quantum computation schemes. In previous reports, TINWs grown by the usual vapour-liquid-solid (VLS) method offer limited possibilities for device layouts and their finite bulk transport contribution yet showed potential for improvements.

We have been performing fabrication of TINWs based on an alternative and scalable approach, namely, etching of bulk-insulating MBE-grown high-quality (Bi_1−xSb_x)₂Te₃ thin films. So far, we have been able to prepare such top-down TINWs with a quality close to that of the pristine films and to achieve high gate tuneability. However, proximity-induced superconductivity was never achieved in such systems. In this presentation, we report our success in observing proximity-induced superconductivity in these TINWs and present our characterizations based on Josephson junctions. These results enable further studies on narrower TINWs with quantized 1D surface subbands, which could potentially host MBS when proximitized.