Persistent surface states with diminishing gap in MnBi2Te4/Bi2Te3 superlattice antiferromagnetic topological insulator

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2020,（24）
• 所属期刊栏目: ARTICLES
• 页码范围: 2086-2093
• 页数: 8页
• 语种: 英文

摘要

Magnetic topological quantum materials(TQMs)provide a fertile ground for the emergence of fascinating topological magneto-electric effects.Recently,the discovery of intrinsic antiferromagnetic(AFM)topo-logical insulator MnBi2Te4 that could realize quantized anomalous Hall effect and axion insulator phase ignited intensive study on this family of TQM compounds.Here,we investigated the AFM compound MnBi4Te7 where Bi2Te3 and MnBi2Te4 layers alternate to form a superlattice.Using spatial-and angle-resolved photoemission spectroscopy,we identified ubiquitous(albeit termination dependent)topolog-ical electronic structures from both Bi2Te3 and MnBi2Te4 terminations.Unexpectedly,while the bulk bands show strong temperature dependence correlated with the AFM transition,the topological surface states with a diminishing gap show negligible temperature dependence across the AFM transition.Together with the results of its sister compound MnBi2Te4,we illustrate important aspects of electronic structures and the effect of magnetic ordering in this family of magnetic TQMs.