Unveiling unconventional magnetism at the surface of Sr2RuO4

R. Fittipaldi, R. Hartmann, M. T. Mercaldo, S. Komori, A. Bjørlig, W. Kyung, Y. Yasui, T. Miyoshi, L. A.B. Olde Olthof, C. M. Palomares Garcia, V. Granata, I. Keren, W. Higemoto, A. Suter, T. Prokscha, A. Romano, C. Noce, C. Kim, Y. Maeno, E. ScheerB. Kalisky, J. W.A. Robinson, M. Cuoco, Z. Salman, A. Vecchione, A. Di Bernardo

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Materials with strongly correlated electrons often exhibit interesting physical properties. An example of these materials is the layered oxide perovskite Sr2RuO4, which has been intensively investigated due to its unusual properties. Whilst the debate on the symmetry of the superconducting state in Sr2RuO4 is still ongoing, a deeper understanding of the Sr2RuO4 normal state appears crucial as this is the background in which electron pairing occurs. Here, by using low-energy muon spin spectroscopy we discover the existence of surface magnetism in Sr2RuO4 in its normal state. We detect static weak dipolar fields yet manifesting at an onset temperature higher than 50 K. We ascribe this unconventional magnetism to orbital loop currents forming at the reconstructed Sr2RuO4 surface. Our observations set a reference for the discovery of the same magnetic phase in other materials and unveil an electronic ordering mechanism that can influence electron pairing with broken time reversal symmetry.

Original languageEnglish
Article number5792
JournalNature Communications
Volume12
Issue number1
DOIs
StatePublished - 4 Oct 2021

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).

Funding

A.D.B. and R.H. acknowledge funding from the Humboldt Foundation in the framework of a Sofja Kovalevskaja grant endowed by the Alexander von Humboldt foundation. A.D.B. also acknowledges funding from the Zukunftskolleg at the University of Kon-stanz. Y.M. acknowledges support from the JSPS (Nos. JP15H05852, JP15K21717, and JP17H06136) and, along with R.F., M.T.M., S.K., Y.Y., T.M., L.A.B.O.O., C.M.P.G., V.G., W.H., J.R., M.C., A.V., from the JSPS-EPSRC-CNR-IBS Core-to-core programme Oxide Superspin (Nos. EP/P026311/1 and JPJSCCA2017002). A.B. and B.K. acknowledge the European Research Council (Grant No. ERC-2019-COG-866236), the Israeli Science Foundation (Grant No. ISF-1251/19), the QuantERA ERA-NET (Project No. 731473). W.K. and C.K. acknowledge support from the Institute for Basic Science in Korea (Grant No. IBS-R009-G2). We also acknowledge A. Fittipaldi for support during the preparation of the experiment.

FundersFunder number
JSPS-EPSRC-CNR-IBS
QuantERA ERA-NET731473
Zukunftskolleg at the University of Kon-stanz
Alexander von Humboldt-Stiftung
H2020 European Research Council
Engineering and Physical Sciences Research CouncilEP/P026311/1
European CommissionERC-2019-COG-866236
Japan Society for the Promotion of ScienceJPJSCCA2017002, JP15H05852, JP15K21717, JP17H06136
Korea Basic Science InstituteIBS-R009-G2
Israel Science FoundationISF-1251/19

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