Strong correlations and topology in 2D semiconductor moiré superlattices

二维半导体莫尔超晶格中的强关联和拓扑

报告人: 李听昕 , 上海交通大学 物理与天文学院

时    间：2024年11月14日  15:00

地    点：沙河校区物理学院C511

Abstract:

Two-dimensional (2D) semiconducting transition metal dichalcogenide (TMDc) moiré superlattices have emerged as a highly tunable platform for investigating novel quantum states of matter arising from strong electronic correlations and nontrivial band topology. We have successfully realized highly tunable topological flat bands in both TMDc heterobilayer and TMDc homobilayer moiré superlattices. Specifically, by performing low-temperature transport measurements, we have observed a robust integer quantum anomalous Hall (IQAH) effect and signatures of quantum spin Hall effect in WSe2/MoTe2 moiré heterostructures. Remarkably, both the IQAH effect and the long-sought fractional quantum anomalous Hall (FQAH) effect have been observed in twisted bilayer MoTe2. Moreover, ferromagnetism and Chern insulator states have also been observed in the second moiré band of twisted MoTe2. The band topology in TMDc moiré superlattices is highly tunable by external electric field and magnetic field, which enable us to realize novel topological quantum phase transitions. Our studies pave the path for the investigation of fractional phases of matter and anyonic statistics at zero magnetic field based on 2D moiré materials.

About the Speaker:

上海交通大学副教授，入选国家海外高层次人才引进计划青年项目。
2011年在西北大学获得物理学学士学位，2016年于北京大学物理学院获得博士学位，2016年至2021年先后在美国莱斯大学和美国康奈尔大学从事博士后研究，2021年6月加入上海交通大学物理与天文学院。近年来在二维半导体莫尔超晶格、石墨烯、分数量子反常霍尔效应实验证明等研究方向取得了优秀的学术成果，发表期刊论文30余篇，包括第一/通讯作者的 Nature 3篇、Nature 子刊 4篇、Physical Review X 2篇，Physical Review Letters 2篇。