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Proceedings Paper

Exploiting topological matter for Majorana physics and devices via molecular beam epitaxy (Conference Presentation)
Author(s): Peter Schüffelgen; Daniel Rosenbach; Chuan Li; Tobias W. Schmitt; Michael Schleenvoigt; Sarah Schmitt; Abdur R. Jalil; Jonas Kölzer; Lidia Kibkalo; Martina Luysberg; Benjamin Bennemann; Umut Parlak; Doris Meertens; Stephan Trellenkamp; Gregor Mussler; Thomas Grap; Meng Wang; Erwin J. Berenschot; Niels R Tas; Alexander A. Golubov; Alexander Brinkman; Thomas Schäpers; Detlev Grützmacher

Paper Abstract

In this work, a novel fabrication technique is presented, which allows to construct topological insulator - superconductor (TI-SC) hybrid devices of high quality under UHV conditions. A stencil mask is applied to the substrate before growth of (Bi,Sb)2Te3 TI thin films by means of molecular beam epitaxy. The shadow mask is used for stencil lithography of superconductive electrodes on top of the topological thin films. Finally, the ready devices are covered with a capping layer to protect the surfaces of TI and S from oxidation at ambient conditions. Besides the full device fabrication under UHV conditions, it is important to choose the right material combination. While superconductive aluminum (Al) electrodes on top of (Bi,Sb)2Te3 thin films yielded a low interface quality, measurements on (Bi,Sb)2Te3 films with niobium (Nb) electrodes, however, provided a high interface transparency. In radio frequency experiments a missing first Shapiro step was detected in our Nb - (Bi,Sb)2Te3 - Nb junctions, indicating signatures of Majorana bound states. To exploit our stencil technique to more complex device layouts for proposed topological quantum computational applications, the mask was attached to pre-patterned Si substrates. This allowed us to combine selective area growth of topological nanostructures and stencil lithography of superconductive electrodes with nm precision, paving the way for fabrication of elaborated Majorana devices.

Paper Details

Date Published: 10 September 2019
Proc. SPIE 11090, Spintronics XII, 110902D (10 September 2019); doi: 10.1117/12.2527294
Show Author Affiliations
Peter Schüffelgen, Forschungszentrum Jülich GmbH (Germany)
Daniel Rosenbach, Forschungszentrum Jülich GmbH (Germany)
Chuan Li, MESA+ Institute for Nanotechnology, Univ. of Twente (Netherlands)
Tobias W. Schmitt, RWTH Aachen Univ. (Germany)
Michael Schleenvoigt, Forschungszentrum Jülich GmbH (Germany)
Sarah Schmitt, Forschungszentrum Jülich GmbH (Germany)
Abdur R. Jalil, Forschungszentrum Jülich GmbH (Germany)
Jonas Kölzer, Forschungszentrum Jülich GmbH (Germany)
Lidia Kibkalo, Forschungszentrum Jülich GmbH (Germany)
Martina Luysberg, Forschungszentrum Jülich GmbH (Germany)
Benjamin Bennemann, Forschungszentrum Jülich GmbH (Germany)
Umut Parlak, Forschungszentrum Jülich GmbH (Germany)
Doris Meertens, Forschungszentrum Jülich GmbH (Germany)
Stephan Trellenkamp, Forschungszentrum Jülich GmbH (Germany)
Gregor Mussler, Forschungszentrum Jülich GmbH (Germany)
Thomas Grap, RWTH Aachen Univ. (Germany)
Meng Wang, Shanghai Institute of Microsystem and Information Technology (China)
Erwin J. Berenschot, MESA+ Institute for Nanotechnology, Univ. of Twente (Netherlands)
Niels R Tas, MESA+ Institute for Nanotechnology, Univ. of Twente (Netherlands)
Alexander A. Golubov, MESA+ Institute for Nanotechnology, Univ. of Twente (Netherlands)
Alexander Brinkman, MESA+ Institute for Nanotechnology, Univ. of Twente (Netherlands)
Thomas Schäpers, Forschungszentrum Jülich GmbH (Germany)
Detlev Grützmacher, Forschungszentrum Jülich GmbH (Germany)

Published in SPIE Proceedings Vol. 11090:
Spintronics XII
Henri-Jean M. Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi, Editor(s)

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