Current-Phase Relation of a WTe2Josephson Junction

Martin Endres; Artem Kononov; Hasitha Suriya Arachchige; Jiaqiang Yan; David Mandrus; Kenji Watanabe; Takashi Taniguchi; Christian Schönenberger

doi:10.1021/acs.nanolett.3c01416

Current-Phase Relation of a WTe₂Josephson Junction

Martin Endres, Artem Kononov, Hasitha Suriya Arachchige, Jiaqiang Yan, David Mandrus, Kenji Watanabe, Takashi Taniguchi, Christian Schönenberger

Correlated Electron Materials

Research output: Contribution to journal › Article › peer-review

16 Scopus citations

Abstract

When a topological insulator is incorporated into a Josephson junction, the system is predicted to reveal the fractional Josephson effect with a 4π-periodic current-phase relation. Here, we report the measurement of a 4π-periodic switching current through an asymmetric SQUID, formed by the higher-order topological insulator WTe₂. Contrary to the established opinion, we show that a high asymmetry in critical current and negligible loop inductance are not sufficient by themselves to reliably measure the current-phase relation. Instead, we find that our measurement is heavily influenced by additional inductances originating from the self-formed PdTe_xinside the junction. We therefore develop a method to numerically recover the current-phase relation of the system and find the 1.5 μm long junction to be best described in the short ballistic limit. Our results highlight the complexity of subtle inductance effects that can give rise to misleading topological signatures in transport measurements.

Original language	English
Pages (from-to)	4654-4659
Number of pages	6
Journal	Nano Letters
Volume	23
Issue number	10
DOIs	https://doi.org/10.1021/acs.nanolett.3c01416
State	Published - May 24 2023

Funding

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme: grant agreement No. 787414 TopSupra, by the Swiss National Science Foundation through the National Centre of Competence in Research Quantum Science and Technology (QSIT), and by the Swiss Nanoscience Institute (SNI). A.K. was supported by the Georg H. Endress foundation. D.M. and J.Y. acknowledge support from the U.S. Department of Energy (U.S.-DOE), Office of Science-Basic Energy Sciences (BES), Materials Sciences and Engineering Division. H.S.A. was supported by the Gordon and Betty Moore Foundation’s EPiQS Initiative through Grant GBMF9069 and the Shull Wollan Center Graduate Research Fellowship. D.M. acknowledges support from the Gordon and Betty Moore Foundation’s EPiQS Initiative, Grant GBMF9069. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by MEXT, Japan and the CREST (JPMJCR15F3), JST and from the JSPS KAKENHI (Grant Numbers 19H05790 and 20H00354).

Keywords

WTe
asymmetric SQUID
current-phase relation
edge states
higher-order topological insulators
topological superconductivity

Access to Document

10.1021/acs.nanolett.3c01416

Cite this

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title = "Current-Phase Relation of a WTe2Josephson Junction",

abstract = "When a topological insulator is incorporated into a Josephson junction, the system is predicted to reveal the fractional Josephson effect with a 4π-periodic current-phase relation. Here, we report the measurement of a 4π-periodic switching current through an asymmetric SQUID, formed by the higher-order topological insulator WTe2. Contrary to the established opinion, we show that a high asymmetry in critical current and negligible loop inductance are not sufficient by themselves to reliably measure the current-phase relation. Instead, we find that our measurement is heavily influenced by additional inductances originating from the self-formed PdTexinside the junction. We therefore develop a method to numerically recover the current-phase relation of the system and find the 1.5 μm long junction to be best described in the short ballistic limit. Our results highlight the complexity of subtle inductance effects that can give rise to misleading topological signatures in transport measurements.",

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AU - Endres, Martin

AU - Kononov, Artem

AU - Arachchige, Hasitha Suriya

AU - Yan, Jiaqiang

AU - Mandrus, David

AU - Watanabe, Kenji

AU - Taniguchi, Takashi

AU - Schönenberger, Christian

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