Regensburg 2022 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 22: Unconventional Superconductors

TT 22.1: Hauptvortrag

Mittwoch, 7. September 2022, 15:00–15:30, H10

Evidence for orbital loop current magnetism in Sr₂RuO₄ — R. Fittipaldi¹, R. Hartmann², M.T. Mercaldo¹, S. Komori³, A. Bjørlig⁴, W. Kyung⁵, Y. Yasui⁶, T. Miyoshi⁶, L.A.B. Olde Olthof³, C.M. Palomares Garcia³, V. Granata¹, I. Keren⁷, W. Higemoto⁸, A. Suter⁷, T. Prokscha⁷, A. Romano¹, C. Noce¹, C. Kim⁵, Y. Maeno⁶, E. Scheer², B. Kalisky⁴, J.W.A. Robinson³, M. Cuoco¹, Z. Salman⁷, A. Vecchione¹, and •A. Di Bernardo² — ¹CNR-SPIN, University of Salerno, Italy — ²University of Konstanz, Germany — ³University of Cambridge, UK — ⁴Bar-Ilan University, Israel — ⁵Seoul National University, South Korea — ⁶Kyoto University, Japan — ⁷Paul Scherrer Institute, Switzerland — ⁸Japan Atomic Energy Agency

A deeper understanding of the normal-state properties of Sr₂RuO₄ is crucial also to determine its superconducting state symmetry. Using low-energy muon spin rotation spectroscopy, we have found evidence for a new form of magnetism on the surface of Sr₂RuO₄ in its normal state. We detect weak static dipolar fields with a relatively high onset temperature above 50 K. The magnetism observed is not conventional, and we demonstrate that it arises due to orbital loop currents at the reconstructed Sr₂RuO₄ surface. Our results [1] set a reference for the observation of orbital loop current magnetism in other materials and shed light onto a new mechanism that can affect the superconducting state of Sr₂RuO₄.

[1] R. Fittipaldi et al., Nat. Commun. 12, 5792 (2021)