Magneto-optical Kerr effect in an A-type antiferromagnet
Sunko V, Ahsanullah S, Jain V, Weber S, Kumaran S, Yan J, Orenstein J, Ovchinnikov D. 2026. Magneto-optical Kerr effect in an A-type antiferromagnet. Nature Communications.
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Author
Sunko, VeronikaISTA 
;
Ahsanullah, Salman;
Jain, Vivek;
Weber, Sophie;
Kumaran, Sivaloganathan;
Yan, Jiaqiang;
Orenstein, Joseph;
Ovchinnikov, Dmitry
;
Ahsanullah, Salman;
Jain, Vivek;
Weber, Sophie;
Kumaran, Sivaloganathan;
Yan, Jiaqiang;
Orenstein, Joseph;
Ovchinnikov, DmitryCorresponding author has ISTA affiliation
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Abstract
Magneto-optic Kerr effect (MOKE) is a powerful probe of broken time-reversal symmetry (T), typically used to study ferromagnets. While MOKE has been observed in some antiferromagnets (AFMs) with vanishing magnetization, it is often associated with structures whose symmetry is lower than basic collinear, bipartite order. In contrast, theory predicts a mechanism for MOKE intrinsic to all AFMs of A-type, i.e. layered AFMs in which ferromagnetic layers are antiferromagnetically aligned. Here we report the experimental confirmation of this mechanism in a bulk AFM. We achieve this by measuring the imaginary component of MOKE as a function of photon energy in MnBi2Te4, an A-type AFM where T is preserved in combination with a translation, and comparing the experimental results with model calculations. Our model suggests that observable MOKE should be expected in all collinear A-type AFMs with out-of-plane spin order, thus enabling optical detection of AFM domains and expanding the scope of MOKE to few-layer AFMs.
Publishing Year
Date Published
2026-05-12
Journal Title
Nature Communications
Publisher
Springer Nature
Acknowledgement
We thank Christine Kuntscher for providing optical conductivity and reflectance data published in ref. 33, and Nicola Spaldin, Joel Moore and Bevin Huang for useful discussions. V.S. and J.O. received support from the Gordon and Betty Moore Foundation’s EPiQS Initiative through Grant GBMF4537 awarded to J.O. at UC Berkeley. Experimental and theoretical work at LBNL and UC Berkeley was funded by the Quantum Materials (KC2202) program under the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under Contract No. DE-AC02-05CH11231. Work at the University of Kansas was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, EPSCoR, and Materials Sciences and Engineering Division under Award No. DE-SC0025319. Parts of device fabrication were performed in the KU Nanofabrication Facility, which is supported by the National Institutes of Health NIGMS P30GM145499. Work at ORNL was supported by the U. S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. For the DFT calculations we used resources provided by the Swedish National Infrastructure for Computing (SNIC) at C3SE. We acknowledge support from the US National Science Foundation (NSF) Grant Number 2201516 under the Accelnet program of Office of International Science and Engineering (OISE). This publication is funded in part by a QuantEmX grant from ICAM and the Gordon and Betty Moore Foundation through Grant GBMF9616 to S. K.
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Cite this
Sunko V, Ahsanullah S, Jain V, et al. Magneto-optical Kerr effect in an A-type antiferromagnet. Nature Communications. 2026. doi:10.1038/s41467-026-72577-4
Sunko, V., Ahsanullah, S., Jain, V., Weber, S., Kumaran, S., Yan, J., … Ovchinnikov, D. (2026). Magneto-optical Kerr effect in an A-type antiferromagnet. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-026-72577-4
Sunko, Veronika, Salman Ahsanullah, Vivek Jain, Sophie Weber, Sivaloganathan Kumaran, Jiaqiang Yan, Joseph Orenstein, and Dmitry Ovchinnikov. “Magneto-Optical Kerr Effect in an A-Type Antiferromagnet.” Nature Communications. Springer Nature, 2026. https://doi.org/10.1038/s41467-026-72577-4.
V. Sunko et al., “Magneto-optical Kerr effect in an A-type antiferromagnet,” Nature Communications. Springer Nature, 2026.
Sunko V, Ahsanullah S, Jain V, Weber S, Kumaran S, Yan J, Orenstein J, Ovchinnikov D. 2026. Magneto-optical Kerr effect in an A-type antiferromagnet. Nature Communications.
Sunko, Veronika, et al. “Magneto-Optical Kerr Effect in an A-Type Antiferromagnet.” Nature Communications, Springer Nature, 2026, doi:10.1038/s41467-026-72577-4.
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