Abstract

Fractional Chern insulators are lattice analogs of fractional quantum Hall states without an external magnetic field, which have been observed in twisted bilayer MoTe2 (tMoTe2) and moiré rhombohedral multilayer graphene. In this talk, I will present our theoretical study of Abelian and non-Abelian fractionalized states in tMoTe2, utilizing a continuum model derived from first-principles and the framework of generalized Landau levels (LLs). We develop a variational mapping approach to establish a generalized-LL representation of Bloch bands and apply it to the first two moiré Chern bands in tMoTe2. The first moiré band, dominated by the generalized zeroth LL, supports the formation of Abelian fractional Chern insulators within the Jain sequences. The second moiré band is found to be dominated by the generalized first LL at twist angles around 2 degrees. Numerical calculations at the filling factor 5/2 reveal a competition between the non-Abelian Moore-Read state and a charge density wave state, with the transition controlled by bandwidth, as shown in both exact-diagonalization energy spectra and particle entanglement spectra. These results provide a theoretical foundation for the emergence of fractionalized states in moiré materials.

主讲人简介

吴冯成，武汉大学物理科学与技术学院教授。2011年获得中国科学技术大学学士学位，并于2016年获得德克萨斯大学奥斯汀分校物理学博士学位，导师为Allan H. MacDonald 教授。先后在美国阿贡国家实验室及马里兰大学从事博士后研究，合作导师分别为Ivar Martin 和 Sankar Das Sarma。研究方向为凝聚态理论，致力于低维体系中量子物态的理论研究，在PRL/PRX/PRB，Nature及其子刊，Science 等国际期刊上发表学术论文80余篇。