报告人：Prof. Libor Šmejkal

时 间：2025年11月21日（周五）上午16:00-18:00

地 点：良乡校区，理学楼B多功能厅

摘要：

Identification of altermagnetism based on the recently developed spin-group theory [1] has introduced a collinear class of magnets that is distinct from conventional ferromagnets and antiferromagnets. Altermagnetic d-, g- or i-wave spin order spontaneously breaks spin-rotational symmetry and half of the parent crystallographic symmetries, while those same crystallographic operations combined with specific spin rotations remain symmetries of the altermagnetic statep[1]. In this sense of lattice-symmetry breaking, altermagnets are—similarly to, for example, d-wave superconductors—unconventional and distinct from conventional antiferromagnetic and ferromagnetic exchange nonrelativistic orderings, which do not break the lattice symmetries.

In the first part of the talk, we will outline the origin [2] and theoretical prediction of altermagnetism [1]. We will discuss the predicted unconventional anomalous Hall effect and unusual electronic structure that motivated the symmetry delimitation of altermagnets [2]. We will conclude this section with an overview of photoemission observations of altermagnetic spin splitting [3] and spin polarization [4] in materials with the NiAs crystal structure.

In the second part, we will present our systematic spin-group-theory classification[1,2,5-7] and introduce a distinct class of unconventional spin order—p-wave magnets [5]. Finally, we will explore emerging research directions driven by spin-group-theory insights, including interplay of unconventional magnets with relativity[4] and correlations [8], and spin-transport, multiferroic and topological effects in both unconventional[2,6,9-10] and conventional magnets[7].

[1] PRX 12, 031042 (2022), Phys. Rev. X 12, 040501 (2022), Phys. Rev. Lett. 131, 256703 (2023)

[2] Science Adv. 6, 23 (2020), PNAS 118 42 (2021), Nature Electronics 5 (11), 735-743 (2022), Nature Commun. 15, 4961 (2024).

[3] Nature 626, 517 (2024), Nature Commun. 15, 2116 (2024), PRL 132, 036702 (2024).

[4] arXiv:2511.01690 (2025).

[5] arXiv:2309.01607v3 (2024).

[6] arXiv:2411.19928 (2024).

[7] Phys. Rev. B 111, 085147 (2025).

[8] Phys. Rev. Lett. 132, 236701 (2025), arXiv:2502.19270, PRB, in press (2025), arXiv:2503.10797v1 (2025).

[9] PRX 12, 011028 (2022), Nature Commun. 16 (1), 7270 (2025), arXiv:2503.12203.

[10] Phys. Rev. Lett. 132, 056701 (2024), arXiv:2309.02355 (2023).

简历：

Libor Šmejkal is a head of the Functional Quantum Matter Group at the Max Planck Institute for the Physics of Complex Systems in Dresden. After studying theoretical and experimental physics in Brno and Vienna, he received his PhD in 2020 in Prague and later led a research team in Mainz. His research focuses on quantum matter, including altermagnets and spintronic functionalities. His scientific contributions have been recognized with several awards, including the Walter Schottky Prize (2025), an ERC Starting Grant (2024), the Falling Walls Science Breakthrough of the Year (2023), the European Magnetism Association Young Scientist Award (2021), the Czech Head Prize (2021), and the Siemens Award (2020).

联系方式：wxfeng@bit.edu.cn

邀请人：冯万祥 教授

网 址：http://physics.bit.edu.cn/

承办单位：物理学院、先进光电量子结构设计与测量教育部重点实验室