题目：Topological nodal-line semimetals in ferromagnetic rare-earth-metal monohalides

报告人：聂思敏 博士后

                 斯坦福大学材料科学与工程系

时间：2018年3月29日上午10:00

地点：国家脉冲强磁场科学中心C204

报告摘要：

Topological semimetals, extending the topological classification from insulators to metals, have greatly enriched our understanding of topological states in condensed matter. This is particularly true for topological nodal-line semimetals (TNLSs). In the present paper, we identify layered materials as promising candidates for hosting TNLSs. Based on first-principles calculations and effective model analysis, we propose that layered ferromagnetic rare-earth-metal monohalides LnX (Ln=La, Gd; X=Cl, Br) exhibit long pursued topological phases. Specifically, single-layer LaX and single-layer GdX are ideal two-dimensional (2D) Weyl semimetals and large-gap 2D quantum anomalous Hall insulators (QAHIs), with band gaps up to 61 meV, respectively. In addition, 3D LaX and 3D GdX are TNLSs with a pair of mirror-symmetry protected nodal lines and 3D weak QAHIs, respectively. The nodal lines in 3D LaX extending through the whole Brillouin zone (BZ) are fairly robust against strong spin-orbit coupling (SOC) and located close to the Fermi level, providing a novel platform toward exploring the exotic properties in nodal-line fermions as well as related device designs.

参考文献：

[1] R. Yu et al. Front. Phys. 12, 127202 (2017).

[2] T. Hyart et al. arXiv: 1709.05265 (2017).

[3] J. Ahn et al. PRL 118, 156401 (2017).

[4] S. Nie et al. arXiv: 1803.08486 (2018).

报告人简介：

聂思敏：斯坦福大学材料科学与工程系博士后。2011年本科毕业江西师范大学。2016年中国科学院物理研究所理论物理学博士学位。2016至今于斯坦福大学材料科学与工程系从事博士后研究。目前主要研究方向为固体的拓扑性质研究 。

热忱欢迎广大老师，同学来聆听报告！