Magnetic memory and spontaneous vortices in a van der Waals superconductor

Eylon Persky, Anders V. Bjørlig, Irena Feldman, Avior Almoalem, Ehud Altman, Erez Berg, Itamar Kimchi, Jonathan Ruhman, Amit Kanigel, Beena Kalisky

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

Doped Mott insulators exhibit some of the most intriguing quantum phases of matter, including quantum spin liquids, unconventional superconductors and non-Fermi liquid metals1–3. Such phases often arise when itinerant electrons are close to a Mott insulating state, and thus experience strong spatial correlations. Proximity between different layers of van der Waals heterostructures naturally realizes a platform for experimentally studying the relationship between localized, correlated electrons and itinerant electrons. Here we explore this relationship by studying the magnetic landscape of tantalum disulfide 4Hb-TaS2, which realizes an alternating stacking of a candidate spin liquid and a superconductor4. We report on a spontaneous vortex phase whose vortex density can be trained in the normal state. We show that time-reversal symmetry is broken in the normal state, indicating the presence of a magnetic phase independent of the superconductor. Notably, this phase does not generate ferromagnetic signals that are detectable using conventional techniques. We use scanning superconducting quantum interference device microscopy to show that it is incompatible with ferromagnetic ordering. The discovery of this unusual magnetic phase illustrates how combining superconductivity with a strongly correlated system can lead to unexpected physics.

Original languageEnglish
Pages (from-to)692-696
Number of pages5
JournalNature
Volume607
Issue number7920
DOIs
StatePublished - 28 Jul 2022

Bibliographical note

Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Nature Limited.

Funding

We thank H. Beidenkopf, Y. Dagan, A. Aurbach, E. Shimshoni, R. Ilan, F. de Juan and I. Sochnikov for discussions; and T. R. Devidas for assistance with the NbSe measurements. E.P., A.V.B. and B.K. were supported by the European Research Council grant number ERC-2019-COG-866236, the Israeli Science Foundation grant number ISF-1251/19, COST Action CA16218, the QuantERAERA-NET Cofund in Quantum Technologies, project number 731473 and the Pazy Research Foundation grant number 107-2018. E.B. was supported by the European Research Council grant number ERC-2019-COG-817799. J.R. was supported by the Israeli Science Foundation grant number ISF-994/19. A.K. was supported by Israeli Science Foundation grant number ISF-1263/21. 2

FundersFunder number
Pazy Research FoundationISF-1263/21, 107-2018, ERC-2019-COG-817799, ISF-994/19
European CommissionERC-2019-COG-866236
European Cooperation in Science and Technology731473, CA16218
Israel Science FoundationISF-1251/19

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