报告题目: Integer and fractional quantum anomalous Hall effects in 2D semiconductor moiré superlattices

报告人: 李听昕，上海交通大学

时间地点: 10月25日上午10:00，理科楼C302

摘要：

The emergence of topological moiré flat bands provides exciting opportunities to realize the lattice analogs of both the integer and fractional quantum Hall effects without the need for an external magnetic field. These effects are known as the integer and fractional quantum anomalous Hall (IQAH and FQAH) effects. In this talk, I will mainly present electrical transport studies of moiré superlattices built on 2D transition metal dichalcogenide (TMDc) semiconductors. We have successfully achieved highly tunable topological phases in both TMDc heterobilayer and TMDc homobilayer moiré superlattices. Specifically, we have observed a robust IQAH effect and signatures of quantum spin Hall effect in AB-stacked WSe2/MoTe2. In addition, both the IQAH effect and the long-sought FQAH effect have been realized in twisted bilayer MoTe2. Furthermore, the band topology in TMDc moiré superlattices is highly tunable by external electric fields, which enable us to realize novel topological quantum phase transitions. Our studies pave the path for discovery of a wealth of emergent phenomena arising from the interplay between strong correlations and topology in 2D moiré superlattices.

[1] F. Xu et al. PRX 13, 031037 (2023).

[2] T. Li et al. Nature 600, 641-646 (2021).

[3] T. Li et al. Nature 597, 350-354 (2021).