报告题目（Title）: Multifunctional Quantum States in Kagome Lattices

报告人（Speaker）: 赵俊衡(Jun-Hyung Cho)

报告时间（Time）：2023年4月21日上午10：00-11：00

报告地点（Venue）：实训楼315

报告摘要（Abstract）: The two-dimensional kagome lattice consisting of corner-sharing triangles possesses unique electronic structures characterized by flat bands, Dirac cones, and van Hove singularities, thereby providing a novel platform to investigate various topological and correlated phenomena. Recently, a new family of nonmagnetic layered kagome metals AV₃Sb₅ (A = K, Rb, and Cs) has attracted enormous attention due to its intriguing electronic properties of nontrivial topological states, chiral charge density wave, and superconductivity. In this talk, I will present our first-principles density-functional theory studies for three different kinds of kagome systems: i.e., ferromagnetic Fe₃Sn₂, antiferromagnetic FeSn, and nonmagnetic CsV₃Sb₅. Our findings demonstrate the presence of a flatband ferromagnetism in Fe₃Sn₂ arising from the highly degenerate and dispersionless manifold state of electrons and the symmetry-protected Dirac fermions in the antiferromagnetic FeSn. I also discuss the origin of the charge density wave, the superconducting pairing mechanism, and the pairing symmetry of superconductivity in CsV₃Sb₅.

报告人简介：赵俊衡(Jun-Hyung Cho)教授现为韩国汉阳大学教授，1994年在浦项科技大学获物理学博士学位。毕业后分别在德国马普学会Frit-Haber研究所、美国再生能源国际实验室、美国橡树岭国家实验室、美国田纳西大学、中国科学技术大学等多个国际著名科研机构从事研究工作。2013年受聘河南省特聘讲座教授。赵俊衡教授曾获汉阳大学突出贡献教授奖，韩国纳米突出贡献研究奖，韩国光量子中心突出研究奖等。主要通过理论计算从事材料表面生长、金属绝缘相变、高温超导、拓扑半金属等方面的研究工作，发表在国际一流物理期刊上有150余篇，其中在Physical Review Letters、J Am Chem Soc、Naon Letter等顶尖期刊上发表近30余篇。