Speaker
Description
Since the 1930s, magnetism has been classified into two main branches: ferromagnetism and antiferromagnetism. Recently, we have identified a third fundamental branch: altermagnetism (see Figure). Altermagnetism exhibits a compensated d-, g-, or i-wave alternating spin order and is found in a wide range of materials, from metals to insulators [1]. This discovery emerged from our systematic classification of spin symmetries [1], analogous to the well-established frameworks used in superconductivity, superfluidity, and the Standard Model.
In this talk, we will outline our decade-long journey leading to the discovery of altermagnets, including the prediction and experimental observation of the anomalous Hall effect and unconventional electronic structure in compensated collinear magnets [2]. We will also present our systematic classification, which-beyond even partial-wave altermag-nets recently revealed a new class of odd partial-wave magnets, termed antialtermagnets [3]. Furthermore, we will showcase experimental evidence supporting altermagnetism, including its distinct signatures in photoemission spectra [4] and nanoscale mapping [5]. Finally, we will explore emerging research directions such as altermagnetic spintronics [6], magnonics [7], two-dimensional magnetism [8], and multiferroics [9], along with potential applications of altermagnets both within and beyond solid-state physics [10], including their use in ultrafast and low-power nanoelectronics.
References
[1] L. Šmejkal, J. Sinova, and T. Jungwirth, “Beyond Conventional Ferromagnetism and Antiferromagnetism: A Phase with Nonrelativistic Spin and Crystal Rotation Symmetry,” Phys. Rev. X, vol. 12, no. 3, Sept. 2022, https://doi.org/10.1103/physrevx.12.031042
[2] I. I. Mazin, K. Koepernik, M. D. Johannes, R. González-Hernández, and L. Šmejkal, “Prediction of unconventional magnetism in doped FeSb2,” Proc. Natl. Acad. Sci. U.S.A., vol. 118, no. 42, Oct. 2021, https://doi.org/10.1073/pnas.2108924118
[3] A. B. Hellenes, T. Jungwirth, R. Jaeschke-Ubiergo, A. Chakraborty, J. Sinova, and L. Šmejkal, “P-wave magnets,” 2023, arXiv. https://doi.org/10.48550/ARXIV.2309.01607
[4] J. Krempaský et al., “Altermagnetic lifting of Kramers spin degeneracy,” Nature, vol. 626, no. 7999, pp. 517–522, Feb. 2024, https://doi.org/10.1038/s41586-023-06907-7
[5] O. J. Amin et al., “Nanoscale imaging and control of altermagnetism in MnTe,” Nature, vol. 636, no. 8042, pp. 348–353, Dec. 2024, https://doi.org/10.1038/s41586-024-08234-x
[6] L. Šmejkal, A. B. Hellenes, R. González-Hernández, J. Sinova, and T. Jungwirth, “Giant and Tunneling Magnetoresistance in Unconventional Collinear Antiferromagnets with Nonrelativistic Spin-Momentum Coupling,” Phys. Rev. X, vol. 12, no. 1, Feb. 2022, https://doi.org/10.1103/physrevx.12.011028
[7] L. Šmejkal et al., “Chiral Magnons in Altermagnetic RuO2,” Phys. Rev. Lett., vol. 131, no. 25, Dec. 2023, https://doi.org/10.1103/physrevlett.131.256703
[8] I. Mazin, R. González-Hernández, and L. Šmejkal, “Induced Monolayer Altermagnetism in MnP(S,Se)$_3$ and FeSe,” 2023, arXiv. https://doi.org/10.48550/ARXIV.2309.02355
[9] L. Šmejkal, “Altermagnetic multiferroics and altermagnetoelectric effect,” 2024, arXiv. https://doi.org/10.48550/ARXIV.2411.19928
[10] articles from web, https://www.economist.com/science-and-technology/2024/01/24/scientists-have-found-a-new-kind-of-magnetic-material , https://www.science.org/content/article/researchers-discover-new-kind-magnetism
