Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 100: Topological Insulators II
O 100.1: 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.