The discovery of altermagnetism has been included by Science Magazine in the list of the
"top science breakthroughs of 2024". This discovery is the only entry from the field of physics on the prestigious list, which is led by advances in HIV medicine and also includes the landing of a space rocket.
Altermagnetism was proposed a couple of years ago in a series of articles by Libor Šmejkal, now a group leader at the Max Planck Institute for the Physics of Complex Systems and the Max Planck Institute for the Chemical Physics of Solids, and colleagues from Prague and Mainz. Their initial prediction in 2018 of an unconventional anomalous Hall effect and a complex compensated spin density in direct and momentum space electronic structures paved the way for their systematic spin-symmetry classification in 2021. This classification uncovered altermagnets as a new class of magnets. In altermagnets (example shown in the image), not only the spin polarisation but also the spatial orientation of the adjacent magnetic atoms alternates.
In 2024, researchers published experimental observations of altermagnetism in MnTe and CrSb using momentum-space photoemission spectroscopy at large synchrotron facilities. These experiments were guided by the theoretical work of Libor Šmejkal and his collaborators.
Further reading:
L. Šmejkal
et al., Science Adv.
6, 23 (2020)
I. I. Mazin
et al., PNAS
118, 42 (2021)
L. Šmejkal, J. Sinova, and T. Jungwirth, Phys. Rev. X
12, 031042 (2022)
J. Krempaský, L. Šmejkal, S. W. D'Souza,
et al., Nature
626, 517 (2024)
S. Reimers
et al., Nat. Commun.
15, 2116 (2024)