Persistent surface states with diminishing gap in MnBi_(2)Te_(4)/Bi_(2)Te_(3) superlattice antiferromagnetic topological insulator  

反铁磁拓扑绝缘体MnBi_(2)Te_(4)/Bi_(2)Te_(3)超晶格具有不变近零能隙的表面态研究

作　　者：Lixuan Xu Yuanhao Mao Hongyuan Wang Jiaheng Li Yujie Chen Yunyouyou Xia Yiwei Li Ding Pei Jing Zhang Huijun Zheng Kui Huang Chaofan Zhang Shengtao Cui Aiji Liang Wei Xia Hao Su Sungwon Jung Cephise Cacho Meixiao Wang Gang Li Yong Xu Yanfeng Guo Lexian Yang Zhongkai Liu Yulin Chen Mianheng Jiang 徐丽璇;毛元昊;王洪远;李佳恒;陈宇杰;夏云悠悠;李一苇;裴鼎;张敬;郑慧君;黄逵;张超凡;崔胜涛;梁爱基;夏威;苏豪;Sungwon Jung;Cephise Cacho;王美晓;李刚;徐勇;郭艳峰;杨乐仙;柳仲楷;陈宇林;江绵恒(Center for Excellence in Superconducting Electronics,State Key Laboratory of Functional Material for Informatics,Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences,Shanghai 200050,China;School of Physical Science and Technology,ShanghaiTech University and CAS-Shanghai Science Research Center,Shanghai 201210,China;ShanghaiTech Laboratory for Topological Physics,Shanghai 200031,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha 410073,China;State Key Laboratory of Low Dimensional Quantum Physics,Department of Physics,Tsinghua University,Beijing 100084,China;Department of Physics,Clarendon Laboratory,University of Oxford,Oxford 0X13PU,UK;Advanced Light Source,Lawrence Berkeley National Laboratory,Berkeley,CA 94720,USA;Diamond Light Source,Harwell Campus,Didcot 0X11 ODE,UK;Frontier Science Center for Quantum Information,Beijing 100084,China;RIKEN Center for Emergent Matter Science(CEMS),Wako,Saitama 351-0198,Japan)

机构地区：[1]Center for Excellence in Superconducting Electronics,State Key Laboratory of Functional Material for Informatics,Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences,Shanghai 200050,China [2]School of Physical Science and Technology,ShanghaiTech University and CAS-Shanghai Science Research Center,Shanghai 201210,China [3]ShanghaiTech Laboratory for Topological Physics,Shanghai 200031,China [4]University of Chinese Academy of Sciences,Beijing 100049,China [5]College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha 410073,China [6]State Key Laboratory of Low Dimensional Quantum Physics,Department of Physics,Tsinghua University,Beijing 100084,China [7]Department of Physics,Clarendon Laboratory,University of Oxford,Oxford 0X13PU,UK [8]Advanced Light Source,Lawrence Berkeley National Laboratory,Berkeley,CA 94720,USA [9]Diamond Light Source,Harwell Campus,Didcot 0X11 ODE,UK [10]Frontier Science Center for Quantum Information,Beijing 100084,China [11]RIKEN Center for Emergent Matter Science(CEMS),Wako,Saitama 351-0198,Japan

出　　处：《Science Bulletin》2020年第24期2086-2093,M0005,共9页科学通报（英文版）

基　　金：supported by the National Key Research and Development Program of China (2017YFA0305400, 2017YFA0304600, 2018YFA0307100, and 2018YFA0305603);the National Natural Science Foundation of China (11774190, 11674229, 11634009, 11774427, 51788104, and 11874035);EPSRC Platform Grant (EP/M020517/1);the support from the Shanghai Pujiang Program (17PJ1406200)。

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) topological insulator MnBi_(2)Te_(4) 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 Mn Bi4 Te7 where Bi_(2)Te_(3) and MnBi_(2)Te_(4) layers alternate to form a superlattice. Using spatial-and angleresolved photoemission spectroscopy, we identified ubiquitous(albeit termination dependent) topological electronic structures from both Bi_(2)Te_(3) and MnBi_(2)Te_(4) 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 MnBi_(2)Te_(4), we illustrate important aspects of electronic structures and the effect of magnetic ordering in this family of magnetic TQMs.磁性拓扑材料蕴含拓扑磁电效应等丰富拓扑物理现象,成为近年来拓扑量子材料研究热点.最近,在本征反铁磁拓扑绝缘体MnBi_(2)Te_(4)中发现了量子反常霍尔效应及轴子绝缘体态,使得此体系引发了广泛的关注.由MnBi_(2)Te_(4)及Bi_(2)Te_(3)插层得到的超晶格结构材料(MnBi_(2)Te_(4))m(Bi_(2)Te_(3))n,同样具有本征反磁序及非平庸拓扑相,为研究磁性与拓扑电子结构相互关系提供了重要的可调控材料平台.本文利用具有空间分辨能力的激光和同步辐射角分辨光电子能谱系统(ARPES),全面且系统地测量了此材料体系中Mn Bi4Te7的电子结构,发现在MnBi2Te4及Bi2Te3解理面均存在近零能隙的拓扑表面态;文章通过变温测量,发现其体态电子受到反铁磁序的强烈影响,但其拓扑表面态在反铁磁相变时保持近零能隙不变.这些结果印证了MnBi2Te4体系的不变近零能隙的普遍性,为理解中磁性与拓扑物态之间相互作用以及其调控提供了重要的谱学信息.

关 键 词：Spatially resolved angle-resolved photoemission spectroscopy Electronic band structure Quantum anomalous Hall effect Magnetic topological insulator 

分 类 号：TB34[一般工业技术—材料科学与工程]