摘要
The Mn-Bi-Te class of compounds are recently discovered topological insulators with broken time-reversal-symmetry,which host unique quantum anomalous Hall and axion insulator states.Their key characteristics are believed to be sufficiently understood by models in a single-particle picture.Here,we apply scanning tunneling microscopy to study the electronic properties of MnBi_(2)Te_(4)and MnBi_(4)Te_(7).Unexpectedly,our quasiparticle interference(QPI)results demonstrate that rotational symmetry of the crystal breaks,i.e.a nematic-like pattern arises,in certain energy range but persists in others.Moreover,our data in the presence of an external magnetic field rule out the possibility of the material magnetism as an origin of the C2 symmetric QPI pattern.This study reveals that the interaction in the Mn-Bi-Te class of topological materials may play an essential role in their electronic states,and thus opens a new path for investigating the interplay between wavefunction topology and symmetry breaking phases.
基金
the NSFC(Grants No.11790313,No.92065201,No.11874256,No.11874258,No.12074247,No.12174252,No.11861161003,No.12025404,No.11904165,No.92161201,No.12104221,and No.12074181)
Ministry of Science and Technology of China(Grants No.2019YFA0308600,2020YFA0309000,2017YFA0303203)
the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)
the Science and Technology Commission of Shanghai Municipality(Grants No.2019SHZDZX01,No.19JC1412701,No.20QA1405100)
the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20200312,BK20200310,and BK20190286)or partial support.F.S.Li also acknowledge financial support from the Suzhou Science and Technology Program(Grant No.SJC2021009)and the Youth Innovation Promotion Association of Chinese Academy of Sciences(2017370).
