SKM 2023 – scientific programme

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MA: Fachverband Magnetismus

MA 41: Focus Session: Altermagnetism: Transport, Optics, Excitations

MA 41.1: Invited Talk

Thursday, March 30, 2023, 15:00–15:30, HSZ 02

Altermagnetism and spin symmetries — •Libor Šmejkal — Johannes Gutenberg Universitat Mainz, Germany — Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic

Different phases of matter can be distinguished by symmetries and order parameters. In this talk, we will discuss the classification of magnetically ordered crystals according to recently studied spin symmetries [1]. Spin symmetries consider pairs of operations in spin and crystal space and remarkably reveal an unconventional magnetic class. This unconventional class, called altermagnetism, is sharply distinct from ferromagnets and antiferromagnets. It is characterized by an unconventional alternating spin order in electronic momentum space that breaks time-reversal symmetry and is spin compensated and anisotropic [1,2]. We show that these properties can arise from ordered and anisotropic spin densities and crystal fields, as described for a typical Ruthenium Dioxide altermagnet [1-4]. Finally, we show that altermagnetism provides a unifying explanation for the recently predicted and experimentally observed unconventional anomalous Hall effects in collinear systems without magnetisation [2,3,5 and references therein].

[1] Šmejkal, L., Sinova, J., and Jungwirth, T., Phys. Rev. X 12, 031042 (2022), [2] Šmejkal, L. et al., Science Advances 6, eaaz8809 (2020) [3] Feng, Z., et al. Nature Electron. 5, 735-743 (2022) [4] Šmejkal, L. et al., Phys. Rev. X 12, 011028 (2022) [5] Mazin, I.I et al., PNAS 118 (42) e2108924118 (2021)