Regensburg 2016 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 97: Topological Insulators II (Joint session of DS, HL O and TT, organized by HL)

HL 97.1: Talk

Friday, March 11, 2016, 09:30–09:45, H15

Signatures of induced superconductivity in a p-n heterostructure comprised of Sb₂Te₃ and Bi₂Te₃ 3D topological insulator thin films with in situ Al capping — •Peter Schüffelgen¹, Daniel Rosenbach¹, Martin Lanius¹, Jörn Kampmeier¹, Gregor Mussler¹, Markus Eschbach¹, Ewa Mlynczak¹, Lukasz Plucinski¹, Martina Luysberg¹, Stefan Trellenkamp¹, Martin Stehno², Prosper Ngabonziza², Alexander Brinkman², Yuan Pang³, Li Lu³, Thomas Schäpers¹, and Detlev Grützmacher¹ — ¹Peter Grünberg Institut and JARA-FIT, Forschungszentrum Jülich, 52425 Jülich, Germany — ²TNW and MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands — ³Laboratory for Solid State Quantum Information and Computation, Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, China

We investigate the transport properties of Sb₂Te₃/Bi₂Te₃ p-n heterostructure topological insulator film-superconductor junctions. The films are grown by means of molecular beam epitaxy on a Si (111) substrate and capped in-situ by a thin layer of aluminum to prevent thin film degradation and to preserve the Dirac-like surface states. Josephson junctions are defined by depositing two niobium electrodes, separated by a few tens of nanometers, onto the Sb₂Te₃/Bi₂Te₃ layer. The transport measurements at cryogenic temperatures showed signatures of Andreev reflections and Josephson supercurrents. For wider junctions a Fraunhofer pattern was observed for the critical current, whereas for the narrow junctions a monotonous decrease was found.