Low-energy magnons in the chiral ferrimagnet Cu2OSeO3: A coarse-grained approach

ORAL

Abstract

We report a comprehensive neutron scattering study of low energy magnetic excitations in the breathing pyrochlore helimagnetic Cu2OSeO3. Fully documenting the four lowest energy magnetic modes that leave the ferrimagnetic configuration of the “strong tetrahedra” intact (|\hbar ω|<13 meV), we find gapless quadratic dispersion at the Γ point for energies above 0.2 meV, two doublets separated by 1.6(2) meV at the R point, and a bounded continuum at the X point. Our constrained rigid spin cluster model relates these features to Dzyaloshinskii-Moriya (DM) interactions and the incommensurate helical ground state. Combining conventional spin-wave theory with a spin cluster form factor accurately reproduces the measured equal time structure factor through multiple Brillouin zones. An effective spin Hamiltonian describing complex anisotropic intercluster interactions is obtained.

This work has been published (PhysRevB.101.144411).

*This work was supported as part of the Institute for Quantum Matter, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award No. DESC0019331. Collin Broholm and Jonas Kindervater were supported by the Gordon and Betty Moore Foundation under the EPQS program grant number GBMF9456.

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Presenters

  • Yi Luo

    • Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University
    • Johns Hopkins University

Authors

  • Yi Luo

    • Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University
    • Johns Hopkins University

  • Guy G Marcus

    • Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University
    • Johns Hopkins University

  • Benjamin Trump

    • NIST Center for Neutron Research, National Institute of Standards and Technology

  • Jonas Kindervater

    • Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University

  • Matthew Brandon Stone

    • Oak Ridge National Lab
    • Oak Ridge national lab
    • Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
    • Neutron Scattering Division, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory
    • Oakridge National Laboratory

  • Jose A. Rodriguez-Rivera

    • National Institute of Standard and Technology
    • Center for Neutron Research, NIST
    • NIST
    • NIST Center for Neutron Research, National Institute of Standards and Technology
    • NIST Center for Neutron Research

  • Yiming Qiu

    • NIST Center for Neutron Research, National Institute of Standards and Technology
    • NIST Center for Neutron research, National Institute of Standards and Technology
    • NIST
    • National Institute of Standards and Technology

  • Tyrel McQueen

    • Johns Hopkins University
    • The Johns Hopkins University
    • Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University

  • Oleg Tchernyshyov

    • Johns Hopkins University
    • Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University

  • Collin Leslie Broholm

    • Johns Hopkins University
    • Department of Physics and Astronomy and Institute for Quantum Matter, The Johns Hopkins University
    • Department of Physics and Astronomy and Institute for Quantum Matter, Johns Hopkins University, Baltimore, Maryland 21218, USA
    • Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University
    • Physics, The Johns Hopkins University