Spontaneous emergence of Josephson junctions in homogeneous rings of single-crystal Sr2RuO4

ORAL

Abstract

Sr2RuO4 is expected to be a spin-triplet chiral p-wave superconductor, where the chirality means that the ground state is two-fold degenerate, with two different directions of the Cooper-pair orbital angular momentum. We fabricated Sr2RuO4 microrings and performed resistance (R) and critical-current (Ic) measurements in an axial magnetic field. In some such rings, Little-Parks magnetoresistance oscillations are observed close to the transition temperature Tc as recently reported [1]. In other rings, however, we find that Ic oscillates with a period corresponding to the fluxoid quantization down to temperatures far below Tc. This behavior resembles that of a superconducting quantum interference device (SQUID) and suggests that a pair of weak links of an intrinsic origin is spontaneously formed in the arms of the ring. Such weak links are most naturally attributable to domain walls separating domains with different chirality, which is also the outcome of order parameter calculations. We believe this to be strong new evidence for the chiral superconducting state in Sr2RuO4

[1] Y. Yasui, K. Lahabi, M. S. Anwar, Y. Nakamura, S. Yonezawa, T. Terashima, J. Aarts, and
Y. Maeno, Phys. Rev. B 96, 180507(R) (2017).

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Presenters

  • Jan Aarts

    Huygens-Kamerlingh Onnes Laboratory, Leiden University, Huygens – Kamerlingh Onnes Laboratory, Leiden University

Authors

  • Yuuki Yasui

    Dept. of Physics, Kyoto University

  • Kaveh Lahabi

    Huygens-Kamerlingh Onnes Laboratory, Leiden University

  • Victor Fernandez Becerra

    Dept. of Physics, University of Antwerp

  • Muhammed Shahbaz Anwar

    Dept. of Materials Science and Metallurgy, University of Cambridge

  • Shingo Yonezawa

    Dept. of Physics, Kyoto University, Department of Physics, Kyoto University, Kyoto 606-8502, Japan, Department of Physics, Kyoto University, Japan

  • Takahito Terashima

    Dept. of Physics, Kyoto University

  • Milorad Milosevic

    Dept. of Physics, University of Antwerp

  • Yoshiteru Maeno

    Department of Physics, Kyoto University, Dept. of Physics, Kyoto University, Department of Physics, Graduate School of Science, Kyoto University, Kyoto, Japan, Kyoto University, Department of Physics, Graduate School of Science, Kyoto University, Department of Physics, Kyoto University, Kyoto 606-8502, Japan, Department of Physics, Kyoto University, Japan

  • Jan Aarts

    Huygens-Kamerlingh Onnes Laboratory, Leiden University, Huygens – Kamerlingh Onnes Laboratory, Leiden University