Anomalous open orbits in Hofstadter spectrum of Chern insulator  

作　　者：Haijiao Ji Peng Zhou Noah F.Q.Yuan Hua Jiang Haiwen Liu X.C.Xie 

机构地区：[1]Center for Advanced Quantum Studies,Department of Physics,Beijing Normal University,Beijing,100875,China [2]Tsung-Dao Lee Institute,Shanghai Jiao Tong University,Shanghai,201210,China [3]Department of Mathematics,UC Berkeley,Berkeley,94720,USA [4]Institute for Nanoelectronic Devices and Quantum Computing,Fudan University,Shanghai,200433,China [5]International Center for Quantum Materials,School of Physics,Peking University,Beijing,100871,China [6]Hefei National Laboratory,Hefei,230088,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2025年第3期139-144,共6页中国科学:物理学、力学、天文学(英文版)

基　　金：supported by the National Basic Research Program of China(Grant No.2017YFA0303301);the National Natural Science Foundation of China(Grant Nos.12022407,and 11974256);the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB28000000)。

摘　　要：The nontrivial band topology of Chern insulator can enrich the content of its Hofstadter butterfly spectra,which is closely related to recent experiments in twisted bilayer graphene and cold atom systems.We investigate the Hofstadter spectrum for various models of Chern insulators under a rational fluxφ_(0)/q,hereφ_(0)=h/e and q being an integer.We find the number of splitting subbands is|q-C|with C denoting the Chern number of parent band.Importantly,anomalous open-orbital subbands with Chern numbers q-1 and-q-1 emerge unexpectedly,which are beyond the parameter window(-q/2,q/2)of the Diophantine equation studied by Thouless-Kohmoto-Nightingale-den Nijs[Phys.Rev.Lett.49,405(1982)].The emergence of anomalous open orbits can be traced by analyzing the evolution of the Hofstadter spectrum,identifying as a new type of topological phase transition.These novel findings not only pinpoint the peculiar Hofstadter spectrum of Chern insulator,but also provide routes to study exotic characteristics beyond the Landau level physics.

关 键 词：Hofstadter spectrum topological phase transition open orbit 

分 类 号：O469[理学—凝聚态物理]