PGI-1 Talk: Prof. Dr. Kunihiko Yamauchi

Quantum Theory of Materials Seminar / *Two Invited Talks today*

DFT Calculation and Magnetic Symmetry Analysis on Altermagnets

“Altermagnetism” has emerged as a new class of magnetism, manifesting the spin splitting phenomena in the reciprocal space owing to the magnetic ordering that breaks the PT (parity and time-reversal) symmetry while the alternating spin configuration leads to vanishing magnetization in real space [1]. Several collinear antiferromagnetic materials are identified to exhibit altermagnetism, including RuO2 and MnTe [2]. Recently, we have reported a theoretical study on CaCrO3 as a prototypical perovskite transition-metal oxide that exhibits the altermagnetism and the sizable anomalous Hall effect [3]. Our symmetry analysis clarified that the antiferromagnetic order parameter belongs to the same irreducible representation as the ferromagnetic order parameter in the nonsymmorphic space group, allowing the nonvanishing Berry curvatures in the reciprocal space. By performing a first-principles calculation, we found that the Berry-curvature “hot spots” lie along the gapped nodal lines where spin-orbit coupling induces the spin splitting of Cr-3d bands near the Fermi energy and enhances the anomalous Hall effect in CaCrO3.

References
[1] L. Šmejkal, J. Sinova, and T. Jungwirth, Phys. Rev. X 12, 031042 (2022);
L. Šmejkal, J. Sinova, and T. Jungwirth, Phys. Rev. X 12, 040501 (2022).
[2] T. Osumi, S. Souma, T. Aoyama, K. Yamauchi, A. Honma, K. Nakayama, T. Takahashi, K. Ohgushi, and T. Sato, Phys. Rev. B 109, 115102 (2024).
[3] T. P. T. Nguyen and K. Yamauchi, Phys. Rev. B 107, 155126 (2023).

*Two Invited Talks today* : Dr. Thi Phuong Thao Nguyen and Prof. Dr. Kunihiko Yamauchi will both give a 25 minutes talk followed by discussion

Contact

Prof. Dr. Stefan Blügel
Phone: +49 2461 61-4249
Email: s.bluegel@fz-juelich.de

Prof. Dr. Kunihiko Yamauchi
Center for Spintronics Research Network, Osaka University, Japan
Email: yamauchi.kunihiko.es@osaka-u.ac.jp