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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.

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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