太阳集团2138登录入口学术报告（第24期）

报告题目:A unified understanding of altermagnets based on C-paired spin-momentum locking

报告专家:刘军伟 教授 香港科技大学

报告时间:2026年05月08日（周五）10:00

报告地点:理6栋302       邀请人:赵纪军

报告内容：

Since proposal in 2022, altermagnetism has become one of most important topics in spintronics, materials science and condensed matter physics, while there are many controversial conclusions. In this talk, I present a unified understanding of unique novel properties of altermagnets and more general unconventional antiferromagnets (AFMs) based on crystal-symmetry-paired spin-valley/momentum locking (CSVL/CSML), which we proposed in 2021[Nat. Commun. 12, 2846 (2021)]. CSML is enabled by the intrinsic crystal symmetries exchanging opposite magnetic sublattices of AFMs (e.g., V₂Se₂O, V₂Te₂O, MnTe and RuO₂) [Nat. Commun. 12, 2846 (2021); Phys. Rev. X 15, 021083 (2025)], and exists in all unconventional AFMs with spin-splitting band structures but not limited to altermagnets. CSML enables unique properties and feasible controls of AFMs by manipulating the corresponding crystal symmetry. Typically, one can use a strain field to induce net valley polarization/magnetization and use an electric field to generate a noncollinear spin current even without spin-orbit coupling. All the predictions, in particular the existence of altermagnetism in V₂(Se, Te)₂O-family materials, have been confirmed in experiments [Nat. Phys. 21, 760 (2025); Nat. Phys. 21, 754 (2025)]. These properties have helped us realize the electric readout and 180^o deterministic switching of the Néel order in our experimental work [Sci. Adv. 10, eadn0479 (2024); Nature 638, 645 (2025)], and motivate us to propose a unified theory of all magnetic deterministic switching [arXiv:2603.29136].

专家简介：

Professor Junwei Liu earned his Ph.D. from Tsinghua University in 2014 and conducted postdoctoral research at MIT from 2014 to 2017. He joined the Hong Kong University of Science and Technology (HKUST) as an Assistant Professor in 2017 and was promoted to Associate Professor in 2023. His recent research focuses on novel quantum phenomena arising from crystal symmetry and his related contributions include (1) theoretical proposal of crystal-symmetry-paired spin-valley locking in collinear spin-splitting antiferromagnets (also named altermagnets) and its realization and experimental verification in V₂(Se, Te)₂O-family materials, which is also the first layered quasi-2D altermagnets; (2) the first electrical readout and 180° switching of the Néel order in a collinear spin-splitting antiferromagnet, and (3) the first demonstration of multiple Majorana zero modes in a single vortex and their hybridization.He has published more than 80 papers, including 2 in Science, 3 in Nature, 2 in Nature Physics, 3 in Nature Materials, 7 in Nature Communications, 1 in Physical Review X, 4 in Physical Review Letters, and 1 in Optica.