Resolving all magnons in antiferromagnetic $\alpha$-RuCl$_3$ by time-domain terahertz spectroscopy

ORAL

Abstract

Spin-1/2 moments in the antiferromagnetic Mott insulator $\alpha$-RuCl$_3$ are coupled by strongly anisotropic bond-dependent exchange interactions on a honeycomb lattice. Intense study of RuCl$_3$ has been driven by the proposal that its low energy excitations may be adiabatically connected to the Majorana quasiparticles. However, the low field magnon behavior and the spin Hamiltonian have not been agreed upon, which is the first step to address whether this material hosts exotic fractionalized excitations. High-resolution time-domain terahertz spectroscopy enables us a systematic study of the field dependence of magnon excitations under an in-plane magnetic field. I will discuss how many magnons there are below the critical field and the dramatic spectral weight shift between them in various geometries. By combining the linear spin-wave theory, our measurements highly constrain the parameters of the spin Hamiltonian.

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Presenters

  • Liang Wu

    • Physics, Univ of California - Berkeley
    • Univ of California - Berkeley
    • Physics, University of California, Berkeley

Authors

  • Liang Wu

    • Physics, Univ of California - Berkeley
    • Univ of California - Berkeley
    • Physics, University of California, Berkeley

  • Erik Aldape

    • Univ of California - Berkeley

  • Arielle Little

    • Univ of California - Berkeley

  • Dylan Rees

    • Univ of California - Berkeley

  • Thomas Scaffidi

    • Physics, Univ of California - Berkeley
    • Physics, University of California, Berkeley
    • Univ of California - Berkeley
    • University of Oxford

  • Paula Kelley

    • Oak Ridge National Lab
    • Materials Science and Engineering, University of Tennessee

  • Arnab Banerjee

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

  • David Mandrus

    • Department of Materials Science and Engineering, The University of Tennessee
    • Oak Ridge National Lab
    • Oak Ridge National Laboratory
    • Department of Materials Science and Engineering, University of Tennessee
    • University of Tennessee
    • Materials Science and Technology, Oak Ridge National Laboratory
    • Materials Science and Engineering, The University of Tennessee
    • Materials Science and Engineering, University of Tennessee
    • Material Science and Technology Division, Oak Ridge National Laboratory
    • Oakridge National Laboratory
    • University of Tennessee, Knoxville
    • Univ of Tennessee, Knoxville

  • Stephen Nagler

    • Quantum Condensed Matter Division, Oak Ridge National Laboratory
    • Oak Ridge National Lab
    • Oak Ridge National Laboratory
    • Neutron Scattering Division, Oak Ridge National Laboratory

  • Ehud Altman

    • Univ of California - Berkeley
    • Physics, Univ of California - Berkeley

  • Joseph Orenstein

    • Physics, Univ of California - Berkeley
    • Univ of California - Berkeley
    • Physics, University of California, Berkeley