Novel Excitations near Quantum Criticality in Geometrically Frustrated Antiferromagnet CsFeCl<sub>3</sub>

 · Invited

Abstract

The investigation of materials that exhibit quantum phase transition provides valuable insights into fundamental problems in physics. We present neutron scattering under pressure in a triangular-lattice antiferromagnet that has a quantum disorder in the low-pressure phase and a noncollinear structure in the high-pressure phase [1]. The neutron spectrum continuously evolves through critical pressure; a single mode in the disordered state becomes soft with the pressure and it splits into gapless and gapped modes in the ordered phase. Extended spin-wave theory reveals that the longitudinal and transverse fluctuations of spins are hybridized in the modes because of noncollinearity, and novel magnetic excitations are formed. We report a new hybridization of the phase and amplitude fluctuations of the order parameter near a quantum critical point in a spontaneously symmetry-broken state.
[1] S. Hayashida et al., Sci. Adv. 5, eaaw5639 (2019).

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Presenters

  • Takatsugu Masuda

    • Institute for Solid State Physics, Univ of Tokyo

Authors

  • Takatsugu Masuda

    • Institute for Solid State Physics, Univ of Tokyo

  • Shohei Hayashida

    • Laboratory for Solid State Physics, ETH Zurich, Switzerland
    • ETH Zurich
    • Institute for Solid State Physics, Univ of Tokyo

  • Masashige Matsumoto

    • Shizuoka University

  • Masato Hagihala

    • KEK, High Energy Accelerator Research Organization
    • High Energy Accelerator Research Organization

  • Nobuyuki Kurita

    • Department of Physics, Tokyo Institute of Technology
    • Tokyo Institute of Technology

  • Hidekazu Tanaka

    • Department of Physics, Tokyo Institute of Technology
    • Tokyo Institute of Technology

  • Shinichi Itoh

    • High Energy Accelerator Research Organization

  • Tao Hong

    • Oak Ridge National Lab
    • Neutron Scattering Division, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory
    • Oak Ridge National Lab, Neutron Scattering Division

  • Minoru Soda

    • Ochanomizu University

  • Yoshiya Uwatoko

    • Institute for Solid State Physics, University of Tokyo
    • Institute for Solid State Physics, The University of Tokyo
    • Institute for Solid State Physics, Univ of Tokyo