Time: 10:00am (UTC/GMT+8:00, Beijing/Shanghai), Jun. 23, 2021

Venue: KITS Meeting Room, No. 7 Building, UCAS [View Map]

Speaker: Binbin Chen (BUAA）

Abstract:

Magic-angle twisted bilayer graphene (TBG) has recently become a new material platform realizing correlated electron phenomena taking place within its topological flat bands. Several numerical and analytical methods have been applied to understand the correlated phases of TBG, revealing some similarity with the quantum Hall physics.

In this talk, I'll present our recent work on a TBG-related lattice model which provide a Mott-Hubbard perspective for the TBG system. By employing the large-scale density matrix renormalization group (DMRG) on the lattice model containing the projected Coulomb interactions only, we identify a quantum anomalous Hall (QAH) state with Chern number of ±1, and an insulating stripe state, separated by a first-order quantum phase transition.

Our results shed light on the mechanism of QAH discovered at three-quarters filling, and provide a first instance of the topological Mott insulator, i.e., the QAH state in the strong coupling limit.

About the Speaker:

陈斌斌 （北京航空航天大学物理学院）

个人经历：

2015年9月 – 2021年 6月  北京航空航天大学 物理学院 博士学习

2018年 2 月 – 2020 年 2 月  德国慕尼黑大学 Jan von Delft研究组 联合培养

2021 年 5月 至今  国科大卡夫里理论科学研究所 苏刚教授研究组 访问交流

主要研究量子多体系统中的张量网络方法，以及利用张量网络算法研究凝聚态物理中的前沿问题，如与铜氧体高温超导、魔转角石墨烯等相关的强关联模型中的新奇量子物态。

Invited by Prof. Long Zhang