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Constraints on the superconducting order parameter in Sr<sub>2</sub>RuO<sub>4</sub> from oxygen-17 nuclear magnetic resonance

ORAL

Abstract

The superconducting state of the quasi two-dimensional and strongly correlated perovskite Sr2RuO4 is considered to be a solid-state analogue to the superfluid 3He-A phase, with an odd-parity order parameter that breaks time-reversal symmetry. Recent experiments using in-plane uniaxial stress revealed a dramatic rise and peak of the transition temperature [1], related to a DOS enhancement [2]. Here we use 17O NMR spectroscopy to probe the nature of superconductivity in Sr2RuO4 and its evolution under uniaxial strain. A reduction of the Knight shift is observed below Tc for all strain values, consistent with a drop in spin polarization in the superconducting state [3]. In unstrained samples, our results rule out a chiral p-wave order parameter. We discuss the issue of sample heating on a sub-millisecond time scale after the NMR pulse, which is particularly relevant to superconductors with a small transition temperature (Tc ≈ 1 K).

[1] Science 355, eaaf9398 (2017)
[2] Phys. Rev. X, 9, 021044 (2019)
[3] Nature 574, 72–75 (2019)

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Presenters

  • Andrej Pustogow

    University of California, Los Angeles

Authors

  • Andrej Pustogow

    University of California, Los Angeles

  • Yongkang Luo

    Huazhong University of Science and Technology, University of California, Los Angeles, Huazhong University of Science & Technology

  • Aaron Chronister

    University of California, Los Angeles

  • Yue-Shun Su

    University of California, Los Angeles

  • Dmitry Sokolov

    Max Planck Institute for Chemical Physics of Solids, MPI CPfS, Dresden, Germany, Max Planck Institute for Chemical Physics of Solids, Dresden, Germany

  • Fabian Jerzembeck

    Max Planck Institute for Chemical Physics of Solids, Max Planck Institute for Chemical Physics of Solids, Dresden, Germany

  • Andrew P. Mackenzie

    Max Planck Institute for Chemical Physics of Solids, Max Planck Institute for Chemical Physics of Solids, Dresden, Germany

  • Clifford W. Hicks

    Max Planck Institute for Chemical Physics of Solids, MPI CPfS, Dresden, Germany, Max Planck Institute for Chemical Physics of Solids, Dresden, Germany

  • Naoki Kikugawa

    5National Institute for Material Science, Japan, National Institute for Material Science, Tsukuba Japan, National Institute for Material Science, Japan, National Institute for Materials Science, Tsukuba, Japan

  • Srinivas Raghu

    Institute for Materials and Energy Sciences, Stanford University, Stanford Univ, Stanford University, Stanford

  • Eric Bauer

    Los Alamos National Laboratory, Los Alamos Natl Lab, Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, Los Alamos National Laboratory, Los Alamos

  • Stuart Brown

    University of California, Los Angeles