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Proximity-induced odd-frequency superconductivity in a topological insulator

Krieger, Jonas A., Pertsova, Anna, Giblin, Sean R., Döbeli, Max, Prokscha, Thomas, Schneider, Christof W., Suter, Andreas, Hesjedal, Thorsten, Balatsky, Alexander V. and Salman, Zaher 2020. Proximity-induced odd-frequency superconductivity in a topological insulator. Physical Review Letters 125 (2) , 026802. 10.1103/PhysRevLett.125.026802

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Abstract

At an interface between a topological insulator (TI) and a conventional superconductor (SC), superconductivity has been predicted to change dramatically and exhibit novel correlations. In particular, the induced superconductivity by an s-wave SC in a TI can develop an order parameter with a p-wave component. Here we present experimental evidence for an unexpected proximity-induced novel superconducting state in a thin layer of the prototypical TI, Bi2Se3 proximity coupled to Nb. From depth-resolved magnetic field measurements below the superconducting transition temperature of Nb, we observe a local enhancement of the magnetic field in Bi2Se3 that exceeds the externally applied field, thus supporting the existence of an intrinsic paramagnetic Meissner effect arising from an odd-frequency superconducting state. Our experimental results are complemented by theoretical calculations supporting the appearance of such a component at the interface which extends into the TI. This state is topologically distinct from the conventional Bardeen-Cooper-Schrieffer state it originates from. To the best of our knowledge, these findings present a first observation of bulk odd-frequency superconductivity in a TI. We thus reaffirm the potential of the TI-SC interface as a versatile platform to produce novel superconducting states.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Publisher: American Physical Society
ISSN: 0031-9007
Date of First Compliant Deposit: 14 July 2020
Date of Acceptance: 16 June 2020
Last Modified: 15 Jul 2020 16:00
URI: http://orca.cf.ac.uk/id/eprint/133418

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