Nanocalorimetric Evidence for Nematic Superconductivity in Sr<sub>0.1</sub>Bi<sub>2</sub>Se<sub>3</sub>

ORAL

Abstract

Spontaneous rotational-symmetry breaking in the superconducting state of doped Bi2Se3 has attracted significant attention as an indicator for topological superconductivity. High-resolution calorimetry of single-crystal Sr0.1Bi2Se3 provides unequivocal evidence of a twofold rotational symmetry in the superconducting gap by a bulk thermodynamic probe, a fingerprint of nematic superconductivity. The extremely small specific heat anomaly resolved with our high-sensitivity technique is consistent with the material's low carrier concentration proving bulk superconductivity. The large basal-plane anisotropy of Hc2 is attributed to a nematic phase of a two-component topological gap structure η = (η1, η2) and caused by a symmetry-breaking energy term δ(|η1|2 - (|η2|2) Tc. A quantitative analysis of our data excludes more conventional sources of this two-fold anisotropy and provides the first estimate for the symmetry-breaking strength δ ~ 0.1.

*This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. K. W. and R. W. acknowledge support from the Swiss National Science Foundation through the Postdoc Mobility program.

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Presenters

  • Ulrich Welp

    • Materials Science Division, Argonne National Laboratory
    • Argonne National Laboratory

Authors

  • Kristin Willa

    • Materials Science Division, Argonne National Laboratory
    • Argonne National Laboratory

  • Roland Willa

    • Materials Science Division, Argonne National Laboratory
    • Argonne National Laboratory

  • Kok Wee Song

    • Materials Science Division, Argonne National Laboratory

  • Genda Gu

    • Brookhaven National Laboratory
    • Brookhaven National Lab
    • Department of Condensed Matter Physics and Materials Science, Brookhaven, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
    • Cond. Matt. Physics and Material Science, Brookhaven Natl Lab
    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory
    • Condensed Matter Physics & Materials Science Department, Brookhaven National Laboratory
    • Brookhaven National Labs, Long Island, NY, USA, 11973
    • Condensed Matter Physics & Materials Science, Brookhaven National Laboratory
    • Condensed Matter Physics, Brookhaven National Laboratory
    • Brookhaven National Laboratories
    • Chinese Academy of Sciences
    • Condensed Matter Physics & Materials Science, Brookhaven National Lab
    • Brookhaven Natl Lab

  • Ruidan Zhong

    • Brookhaven National Lab
    • Department of Chemistry, Princeton University
    • Department of Condensed Matter Physics and Materials Science, Brookhaven, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
    • Brookhaven National Laboratory
    • Condensed Matter Physics & Materials Science, Brookhaven National Laboratory
    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory
    • Brookhaven National Laboratories

  • John A. Schneeloch

    • Brookhaven National Laboratory
    • Condensed Matter Physics & Materials Science, Brookhaven National Laboratory
    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory
    • University of Virginia

  • Alexei E Koshelev

    • Materials Science Division, Argonne National Laboratory
    • Argonne National Laboratory

  • Wai-Kwong Kwok

    • Argonne National Laboratory
    • Materials Science Division, Argonne National Laboratory
    • Material Science Division, Argonne National Laboratory
    • Materials Sciences Division, Argonne National Laboratory
    • Argonne National Lab

  • Ulrich Welp

    • Materials Science Division, Argonne National Laboratory
    • Argonne National Laboratory