报告题目：Novel Plasmons in Topological Materials—from the perspective of symmetry and topology

报告人：周建辉 研究院（中国科学院强磁场科学中心）

报告时间：2020年1月9日（周四）14:00-15:00

报告地点：32教218

报告摘要：

The interplay between electron-electron interaction and topology of Bloch electrons in topological materials recently has attracted considerable attentions from both experimental and theoretical aspects. (1) We find that the inverted band structure with the Mexican-hat dispersion could enhance the interband correlation leading to a strong intrinsic plasmon excitation. Its frequency ranges from several meV to tens of meV and can be effectively tuned by the external fields. The electron-hole asymmetric term splits the peak of the plasmon excitation into double peaks. The fate and properties of this plasmon excitation can also act as a probe to characterize the topological phases even in lightly doped systems. We numerically demonstrate the impact of band inversion on plasmon excitations in magnetically doped thin films of three-dimensional strong topological insulators, which support the quantum anomalous Hall states (QAHE). (2) We study the chiral edge plasmons in QAH insulators and find some new and remarkable features. We offer a quantitative explanation for the recent observation of the chiral edge plasmon in QAH insulators. (3) We investigate the impacts of symmetry breaking on the plasmons in monolayer 1T’ transition metal dichalcogenides and predict a new anisotropic acoustic plasmon. (4) Collaborated with experimental group, we find the novel plasmons due to the band inversion in three-dimensional type-II Weyl semimetals and show the splitting of plasmon dispersion by inversion symmetry breaking.

参考文献：

[1] Furu Zhang, Jianhui Zhou, Di Xiao and Yugui Yao, Phys. Rev. Lett. 119, 266804 (2017)

[2] A. C. Mahoney et al, Nat. Commun 8, 1836 (2017);

[3] Furu Zhang, Jianhui Zhou, Di Xiao and Yugui Yao, In preparation (2019);

[4] Changxu Yan, Hao-Ran Chang, Jianhui Zhou et al  In preparation (2019);

[5] Xun Jia, Maoyuan Wang, Jianhui Zhou et al  Under review (2019).

报告人简介：周建辉，中国科学院强磁场科学中心研究员，博士生导师。2012年毕业于中国科学院物理研究所，2012年到2017年先后在美国卡内基梅隆大学和香港大学从事博士后研究，2018年4月加入中科院强磁场科学中心任研究员。长期从事固体中Berry相位效应的研究，目前主要关注综合极端条件下（强磁场、超高压、极低温）拓扑材料中的新奇物性（输运、光学、多体物理）、拓扑材料中的等离激元、凝聚态体系中量子反常相关的物理效应。迄今在Phys Rev Lett、Phys Rev B等国际期刊发表论文近20篇。