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Proximity-Effect-Induced Superconductivity in Nb/Sb2Te3-Nanoribbon/Nb Junctions |
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| Authors: | Jinzhong Zhang Abdur Rehman Jalil Pok-Lam Tse Jonas Kölzer Daniel Rosenbach Helen Valencia Martina Luysberg Martin Mikulics Gregory Panaitov Detlev Grützmacher Zhigao Hu Jia Grace Lu Thomas Schäpers |
| Affiliation: | 1. Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich, 52425, Jülich, Germany JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425, Jülich, Germany Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Materials, School of Physics and Electronics Science, East China Normal University, Shanghai, 200241 China;2. Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich, 52425, Jülich, Germany JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425, Jülich, Germany;3. Department of Physics and Astronomy and Department of Electrophysics, University of Southern California, Los Angeles, CA, 90089 USA;4. Ernst Ruska Center, Forschungszentrum Jülich, 52425, Jülich, Germany;5. Institute of Complex Systems (ICS-8) Forschungszentrum Jülich, 52425, Jülich, Germany;6. Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Materials, School of Physics and Electronics Science, East China Normal University, Shanghai, 200241 China;7. Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich, 52425, Jülich, Germany |
| Abstract: | Nanohybrid superconducting junctions using antimony telluride (Sb2Te3) topological insulator nanoribbons and Nb superconducting electrodes are fabricated using electron beam lithography and magnetron sputtering. The effects of bias current, temperature, and magnetic field on the transport properties of the junctions in a four-terminal measurement configuration are investigated. Two features are observed. First, the formation of a Josephson weak-link junction. The junction is formed by proximity-induced areas in the nanoribbon right underneath the inner Nb electrodes which are connected by the few tens of nanometers short Sb2Te3 bridge. At 0.5 K a critical current of 0.15 µA is observed. The decrease of the supercurrent with temperature is explained in the framework of a diffusive junction. Furthermore, the Josephson supercurrent is found to decrease monotonously with the magnetic field indicating that the structure is in the small-junction limit. As a second feature, a transition is also observed in the differential resistance at larger bias currents and larger magnetic fields, which is attributed to the suppression of the proximity-induced superconductive state in the nanoribbon area underneath the Nb electrodes. |
| Keywords: | proximity effect Sb2Te3 nanoribbons superconductivity topological insulators |