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Evidence for even parity unconventional superconductivity in Sr<sub>2</sub>RuO<sub>4</sub>

ORAL

Abstract

The physical picture of unconventional superconductivity (SC) in Sr2RuO4, which was considered a solid-state analogue to the superfluid 3He-A phase for more than two decades [1,2], has been recently overturned [3]. Here we use 17O NMR spectroscopy to probe the nature of the SC state in Sr2RuO4 and its evolution with magnetic field. The drop of Knight shift K is measured in the limit T → 0 across the field-tuned transition down to B/Bc2 < 0.2. While K includes contributions of both field-induced quasiparticles (QP) and a possible spin polarization of the condensate (of order unity for a p-wave state), the specific heat C/T includes only the QP term. By comparing the field dependence of K and C/T, we establish an upper bound for the condensate magnetic response of < 10% of the normal-state susceptibility, which is sufficient to exclude odd-parity candidates [4].

[1] J. Phys. Condens. Matter 7, L643 (1995)
[2] Nature 396, 658–660 (1998)
[3] Nature 574, 72–75 (2019)
[4] arXiv:2007.13730

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Presenters

  • Andrej Pustogow

    University of California, Los Angeles, Department of Physics and Astronomy, University of California, University of Stuttgart

Authors

  • Andrej Pustogow

    University of California, Los Angeles, Department of Physics and Astronomy, University of California, University of Stuttgart

  • Yongkang Luo

    University of California, Los Angeles, Huazhong University of Science & Technology, Huazhong University of Science and 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, Dresden, Germany, Max Planck Institute for Chemical Physics of Solids, Max Planck Institute for the Chemical Physics of Solids

  • Fabian Jerzembeck

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

  • Andrew Mackenzie

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

  • Clifford W Hicks

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

  • Naoki Kikugawa

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

  • Srinivas Raghu

    Stanford University

  • Eric D Bauer

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

  • Stuart Brown

    University of California, Los Angeles