Observation of magnon-polarons in a uniaxial antiferromagnetic insulator Cr<sub>2</sub>O<sub>3</sub>

ORAL

Abstract

Magnon-polarons, a type of hybridized excitations between magnons and phonons, were first reported in yttrium iron garnet as anomalies in the spin Seebeck effect responses. In antiferromagnetic insulators, the magnon spectrum is distinctly different due to the existence of two equivalent, antiferromagnetically coupled spin sub-lattices. Here we report an observation of antiferromagnetic (AFM) magnon-polarons in a uniaxial AFM insulator Cr2O3. Despite the relatively higher energy of magnon than that of the acoustic phonons, near the spin-flop transition of ~ 6 T, the left-handed magnon spectrum shifts downward to hybridize with the acoustic phonons to form AFM magnon-polarons, which can also be probed by the spin Seebeck effect. The spin Seebeck signal is founded to be enhanced due to the magnon-polarons at low temperatures.

*This work was supported as part of the SHINES, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Basic Energy Sciences under Award No. SC0012670.

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Presenters

  • Junxue Li

    • University of California, Riverside
    • Department of Physics and Astronomy, University of California, Riverside

Authors

  • Junxue Li

    • University of California, Riverside
    • Department of Physics and Astronomy, University of California, Riverside

  • Haakon Thømt Simensen

    • Department of Physics, Norwegian University of Science and Technology

  • Derek Reitz

    • Department of Physics and Astronomy, University of California, Los Angeles
    • University of California, Los Angeles

  • Qiyang Sun

    • Department of Mechanical Engineering, University of California, Riverside

  • Wei Yuan

    • University of California, Riverside
    • Department of Physics and Astronomy, University of California, Riverside

  • Chen Li

    • Department of Mechanical Engineering, University of California, Riverside

  • Yaroslav Tserkovnyak

    • University of California, Los Angeles
    • Physics, UCLA
    • Department of Physics and Astronomy, University of California, Los Angeles

  • Arne Brataas

    • Norwegian Univ Tech (NTNU)
    • Department of Physics, Norwegian University of Science and Technology
    • Norwegian University of Science and Technology

  • Jing Shi

    • University of California, Riverside
    • Department of Physics and Astronomy, University of California, Riverside