报告人：

刘奇航

南方科技大学教授

时间：

2023年8月25日上午9:30

地点：

吉林大学中心校区唐敖庆楼B区521报告厅

报告摘要：

       The physical properties in magnetic-ordered materials was ultimately believed to rely on the symmetry theory of magnetic groups. Recently, it has come to light that a more comprehensive group, known as spin group, which combines separate spin and spatial operations, is necessary to fully characterize the geometry and underlying properties of magnetic-ordered materials such as altermagnets [1]. In this talk, we introduce the recent developments of spin group theory, including extensive enumeration of over 100000 spin space groups, identification of spin groups for collinear, coplanar, and noncoplanar configurations, and derivation of irreducible co-representations in momentum space leading to more energy degeneracies that are disallowed by magnetic groups [1,2]. We further show some theoretical and experimental results of spin group applications in understanding physical effects beyond the framework of magnetic groups. Examples include new quasiparticles in antiferromagnet CoNb3S6 [3,4] and new spin splitting effects in antiferromagnets [2,5].
[1] Liu et al. Phys. Rev. X 12, 021016 (2022).
[2] Ren et al. arXiv:2307.10369 (2023).
[3] Liu et al. The Innovation 3, 100343 (2022).
[4] Zhang et al. arXiv:2301.12201 (2023).
[5] Zhu et al. arXiv:2303.04549 (2023).

报告人简介：

       刘奇航，南方科技大学副教授，本科及博士均毕业于北京大学物理学院，曾任美国西北大学博士后、美国科罗拉多大学博尔德分校助理研究员。主要从事计算凝聚态物理研究，研究兴趣聚焦于量子材料中的对称性新理论，多自由度耦合现象新效应，以及相关的新材料设计筛选。发表SCI论文80余篇，H指数35。2018年作为独立PI后发表通讯作者文章30余篇，包括11篇PRL/PRX、4篇Nat. Commun. 、3篇Natl. Sci. Rev.等。2020年作为项目负责人获批国家重点研发计划“量子调控与量子信息”重点专项（青年项目），2022年获批深圳市杰青项目，2021与2022年连续入选斯坦福大学发布的全球前2%顶尖科学家榜单（World’s Top 2% Scientists）。