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Published on: March 24, 2019
Axion electrodynamics in a topologically trivial antiferromagnet
Abhilash Mishra1, Robin Karothiya2, Syed Qamar Abbas Shah1
1Department of Physics & Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, USA.
Nature Communications
|June 20, 2026
Summary
Researchers achieved an isotropic linear magnetoelectric response in chromia, realizing axion electrodynamics in condensed matter. This breakthrough opens doors for novel electronic devices and phenomena.
Area of Science:
- Condensed Matter Physics
- High Energy Physics
- Quantum Electrodynamics
Background:
- Axion electrodynamics, proposed in high energy physics, predicts an isotropic linear magnetoelectric (ME) response.
- Experimental realization of a continuous, purely monopolar ME response has been a significant challenge.
Purpose of the Study:
- To experimentally demonstrate a continuous and purely monopolar isotropic linear ME response.
- To establish chromia as a condensed matter platform for studying axion electrodynamics.
Main Methods:
- Utilizing low-frequency AC ME susceptometry.
- Employing Monte Carlo simulations to support experimental findings.
- Transforming the antiferromagnet chromia into an isotropic ME medium.
Main Results:
- Demonstrated a monopolar ME response (αij = θδij) in chromia, with suppressed quadrupolar contributions.
- Observed a zero crossing of the temperature-dependent θ at 168 K, confirming the axion contribution.
- Established chromia as an isotropic ME medium.
Conclusions:
- The study successfully realized axion electrodynamics in a condensed matter system.
- The findings pave the way for exploring ME Hall effects, magnetophotovoltaic responses, and monopolar devices.
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