Universität zu Köln

Ghatak, Subhamoy, Breunig, Oliver ORCID: 0000-0001-8651-1757, Yang, Fan, Wang, Zhiwei ORCID: 0000-0003-0182-2471, Taskin, Alexey A. and Ando, Yoichi ORCID: 0000-0002-3553-3355 (2018). Anomalous Fraunhofer Patterns in Gated Josephson Junctions Based on the Bulk-Insulating Topological Insulator BiSbTeSe2. Nano Lett., 18 (8). S. 5124 - 5132. WASHINGTON: AMER CHEMICAL SOC. ISSN 1530-6992

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Abstract

One-dimensional Majorana modes are predicated to form in Josephson junctions based on three-dimensional topological insulators (TIs). While observations of supercurrents in Josephson junctions made on bulk-insulating TI samples have been reported recently, the Fraunhofer patters observed in such Tl-based Josephson junctions, which sometimes present anomalous features, are still not well-understood. Here, we report our study of highly gate-tunable Tl-based Josephson junctions made of one of the most bulk-insulating TI materials, BiSbTeSe2, and Al. The Fermi level can be tuned by gating across the Dirac point, and the high transparency of the Al-BiSbTeSe2 interface is evinced by a high characteristic voltage and multiple Andreev reflections, with peak indices reaching 12 Anomalous Fraunhofer patterns with missing lobes were observed in the entire range of gate voltage. We found that, by employing an advanced fitting procedure to use the maximum entropy method in a Monte Carlo algorithm, the anomalous Fraunhofer patterns are explained as a result of inhomogeneous supercurrent distributions on the TI surface in the junction. Besides establishing a highly promising fabrication technology, this work clarifies one of the important open issues regarding Tl-based Josephson junctions.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ghatak, Subhamoy UNSPECIFIED UNSPECIFIED UNSPECIFIED Breunig, Oliver UNSPECIFIED orcid.org/0000-0001-8651-1757 UNSPECIFIED Yang, Fan UNSPECIFIED UNSPECIFIED UNSPECIFIED Wang, Zhiwei UNSPECIFIED orcid.org/0000-0003-0182-2471 UNSPECIFIED Taskin, Alexey A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ando, Yoichi UNSPECIFIED orcid.org/0000-0002-3553-3355 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-177432
DOI:	10.1021/acs.nanolett.8b02029
Journal or Publication Title:	Nano Lett.
Volume:	18
Number:	8
Page Range:	S. 5124 - 5132
Date:	2018
Publisher:	AMER CHEMICAL SOC
Place of Publication:	WASHINGTON
ISSN:	1530-6992
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics II
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ENERGY-GAP STRUCTURE; SUPERCONDUCTING WEAK LINKS; DENSITY DISTRIBUTION; SUPERCURRENT; STATE Multiple languages Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/17743