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

*Alexander von Humboldt Foundation
Julian Schwinger Foundation
1000 Youth Talents Plan of China
JSPS KAKENHI (JP18K04715)
JST-Mirai Program (JPMJMI18A3)
US Department of Energy (DEAC02-76SF00515)
National Science Foundation (DMR-1709304)
LDRD programme of Los Alamos National Laboratory (20170204ER)

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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