题 目：Fractional Chern Insulators in Topological Flat Bands
报告人：刘钊 教授 浙江大学
时 间：2023年9月8号（星期五）
上午 9：30-10：30 上午 10：40-11：40
下午 2：30-3：30 下午 3：40- 5：00
地 点：物理学院LE201
邀请人：胡自翔
报告摘要：Fractional Chern insulators (FCIs) generalize the conventional fractional quantum Hall effect (FQHE) from continuum two-dimensional (2D) electron gases to lattice setups. They typically arise when a nearly flat 2D Bloch band with nonzero Chern number is partially occupied by strongly interacting particles. Band topology and interactions endow FCIs intrinsic topological orders. Since in principle FCIs can exist at zero magnetic field and be protected by a large energy gap, they provide a potentially experimentally more accessible avenue for observing and harnessing FQHE phenomena. Moreover, the interplay between FCIs and lattice-specific effects poses new theoretical challenges.
My lecture has five parts. First, I will briefly review the continuum quantum Hall effect. In the second part, I will talk about the topology and quantum geometry of 2D Bloch bands of lattice systems. When a 2D Bloch band with nonzero Chern number – a Chern band, is fully occupied, integer Chern insulators – the lattice analogues of the continuum integer quantum Hall effect, can emerge. I will give two famous examples of integer Chern insulators. In the third part, I will discuss the FQHE-like states, dubbed FCIs, emerging in a partially filled Chern band. In particular, I will introduce the microscopic models and numerical diagnoses of these states. Then, I will turn to the recent development of FCI, namely the realization of these states in moiré materials. Finally, I will present a summary and list some important open questions.
报告人介绍：Zhao Liu got his PhD degree at Institute of Physics, Chinese Academy of Sciences in 2012. He did postdoctoral research at Princeton University (2013-2015) and Free University Berlin (2015-2018). Since 2018, he is an assistant professor at Physics Department, Zhejiang University. His research interest focuses on strongly-correlated topological phases, disorder and localization, and non-equilibrium dynamics.
