物理学院学术报告（第21期）

报告题目：Spin crystallographic group: theory and applications

报告专家：刘奇航教授    南方科技大学

报告时间：2024年04月08日（周一）10:00

报告地点：理六栋302        邀请人：赵纪军

报告内容：

The physical properties in magnetic-ordered materials were 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 (crystallographic) 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. 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 irreducible co-representations in momentum space leading to more energy degeneracies that are disallowed by magnetic groups. We further show some theoretical and experimental results of spin group applications in understanding physical effects beyond the framework of magnetic groups. Examples include unconventional antiferromagnets with spin splitting, new quasiparticles in antiferromagnet CoNb3S6, and correlation-enhanced spin-orbit coupling effect.

专家简介：

刘奇航，南方科技大学教授，本科及博士均毕业于北京大学物理学院，曾在美国西北大学、科罗拉多大学博尔德分校进行博士后研究。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与新效应，以及相关的新材料设计筛选。发表SCI论文90余篇，H指数36。2018年作为独立PI后发表通讯作者文章40余篇，包括1篇Nature、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青年项目，2022年获批深圳市杰青项目，2021至2023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）。