Bond directional anapole state in a spin-orbit coupled Mott insulator Sr<sub>2</sub>(Ir<sub>1−x</sub>Rh<sub>x</sub>)O<sub>4</sub>

ORAL

Abstract

In a spin-orbit coupled Mott insulator Sr2(Ir1−xRhx)O4, a possible hidden order phase has been reported distinctly above the Néel order phase, accompanying both inversion and time-reversal symmetry breakings. However, the nature of this mysterious phase remains largely elusive. We provide a detailed study of the hidden order phase through the combined study of in-plane magnetic torque and the nematic susceptibility measurements [1]. Our torque magnetometry provides thermodynamic evidence for an electronic nematic transition, breaking C4 rotational symmetry of the underlying lattice. However, in contrast to ordinal even-parity nematic orders, the nematic susceptibility exhibits no divergent behavior towards the onset of the hidden order. These results imply that the nematicity is not a primary order parameter but a secondary one of an odd-parity order parameter. Moreover, our results demonstrate that the hidden order phase is consistent with a bond directional anapole order, in which the intra-unit-cell loop current flows along only one of the diagonal directions in the IrO4 square.
[1] H. Murayama, et al., arXiv:2008.06380.

*This work is supported by KAKENHI, Innovative Areas “Quantum Liquid Crystals” from JSPS, and JST CREST. GC acknowledges NFS support via grant DMR 1903888.

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Presenters

  • Hinako Murayama

    • Department of physics, Kyoto University

Authors

  • Hinako Murayama

    • Department of physics, Kyoto University

  • Kousuke Ishida

    • Department of Advanced Materials Science, The University of Tokyo
    • Department of Advanced Materials Science, the University of Tokyo

  • Ryo Kurihara

    • Department of physics, Kyoto University

  • takahiro ono

    • Department of physics, Kyoto University

  • Yuki Sato

    • Kyoto Univ
    • Physics, Kyoto University
    • Department of physics, Kyoto University

  • Yuichi Kasahara

    • Department of Physics, Kyoto University
    • Kyoto Univ
    • Physics, Kyoto University
    • Department of physics, Kyoto University

  • Hikaru Watanabe

    • Department of physics, Kyoto University

  • Youichi Yanase

    • Kyoto University
    • Kyoto Univ
    • Kyoto Univ.
    • Department of physics, Kyoto University

  • Gang Cao

    • Physics, University of Colorado Boulder
    • University of Colorado, Boulder
    • Department of physics, University of Colorado at Boulder
    • Department of Physics, University of Colorado at Boulder

  • Yuta Mizukami

    • Department of Advanced Material Science, University of Tokyo
    • Department of Advanced Materials Science, University of Tokyo
    • Department of Advanced Materials Science, the University of Tokyo

  • Takasada Shibauchi

    • Department of Advanced Material Science, University of Tokyo
    • Department of Advanced Materials Science, University of Tokyo
    • Department of Advanced Materials Science, The University of Tokyo
    • Dept. Adv. Mat. Sci., Univ. Tokyo
    • Univ of Tokyo-Kashiwanoha
    • Department of Advanced Materials Science, the University of Tokyo

  • Yuji Matsuda

    • Department of Physics, Kyoto University
    • Kyoto Univ
    • Physics, Kyoto University
    • Department of physics, Kyoto University

  • Shigeru Kasahara

    • Department of Physics, Kyoto University
    • Kyoto Univ
    • Department of physics, Kyoto University