Axion electrodynamics in a topologically trivial antiferromagnet

ORAL

Abstract

Axion electrodynamics, proposed by Frank Wilczek, manifests in condensed matter as an isotropic linear magnetoelectric (ME) response[1]. Yet a continuous and purely monopolar ME response has remained elusive. Here, we achieve such a response by transforming the topologically trivial but ME anisotropic antiferromagnet chromia into an isotropic medium by field-cooling a chromia single crystal, followed by low-temperature powdering and solidification. Then we characterize it experimentally using low-frequency AC ME susceptometry and corroborate with Monte Carlo simulations. This procedure suppresses quadrupolar contributions and produces an isotropic ME tensor . Above the Néel temperature, the pure axion response becomes irretrievable, with no known route to recovery, revealing a remarkable asymmetry between the effects of ME annealing before and after powdering. We establish a condensed-matter platform for axion electrodynamics and open routes toward ME Hall phenomena, magnetophotovoltaic effects, and ME monopolar-based devices.

1.  Wilczek F., Phys. Rev. Lett. 58, 1799 (1987)

*Financial support by the NSF through EPSCoR RII Track-1:Emergent Quantum Materials and Technologies Award OIA-2044049 is acknowledged. The research was performed in part in the Nebraska Nanoscale Facility: NNCI and the Nebraska Center for Materials and Nanoscience, which are supported by NSF under Award ECCS: 2025298, and the Nebraska Research Initiative

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Presenters

  • Abhilash Mishra

    • University of Nebraska - Lincoln
    • University of Nebraska -Lincoln, Dept. of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, Lincoln, NE, 68588-0111

Authors

  • Abhilash Mishra

    • University of Nebraska - Lincoln
    • University of Nebraska -Lincoln, Dept. of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, Lincoln, NE, 68588-0111

  • Robin Karothiya

    • Indian Institute of Technology, Mandi

  • Aditi Das

    • University of Nebraska - Lincoln
    • University of Nebraska -Lincoln, Dept. of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, Lincoln, NE, 68588-0111

  • Heejae Cho

    • University of Nebraska-Lincoln
    • University of Nebraska -Lincoln, Dept. of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, Lincoln, NE, 68588-0111

  • Ather Mahmood

    • University of Nebraska - Lincoln
    • University of Nebraska -Lincoln, Dept. of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, Lincoln, NE, 68588-0111

  • Arti Kashyap

    • Indian Institute of Technology, Mandi

  • Christian Binek

    • University of Nebraska - Lincoln
    • University of Nebraska -Lincoln, Dept. of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, Lincoln, NE, 68588-0111