Mott gap engineering in Sr2IrO4/SrTiO3 superlattices  

Sr2IrO4/SrTiO3超晶格中Mott能带结构的调控

作　　者：Xin Liu Yuben Yang Qinghua Zhang Dayu Yan Jingdi Lu Rongyan Chen Youguo Shi Changmin Xiong Fa Wang Lin Gu Jinxing Zhang 刘鑫;杨宇犇;张庆华;闫大禹;鲁京迪;陈荣艳;石友国;熊昌民;王垡;谷林;张金星(Department of Physics,Beijing Normal University,Beijing 100875,China;Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;International Center for Quantum Materials,Peking University,Beijing 100871,China)

机构地区：[1]Department of Physics,Beijing Normal University,Beijing 100875,China [2]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [3]International Center for Quantum Materials,Peking University,Beijing 100871,China

出　　处：《Science China Materials》2020年第9期1855-1860,共6页中国科学（材料科学（英文版）

基　　金：the support from the National Key Research and Development Program of China(2016YFA0302300);CAS Interdisciplinary Innovation Team;the support from the National Natural Science Foundation of China(11974052);Beijing Natural Science Foundation(Z190008);the beamline 1W1A of Beijing Synchrotron Radiation Facility。

摘　　要：In recent years,iridium oxides have attracted intensive research interests both in experiments and theories due to their comparable energy scales of the Coulomb repulsion and strong spin-orbit coupling(SOC)[1,2],where a plenty of novel quantum states such as Weyl semimetal,topological insulator and quantum spin liquid have been studied[3–7].Among the iridates,the layered-perovskite Sr2IrO4(SIO)is a Jeff=1/2 Mott insulating antiferromagnet caused by the interplay of the SOC and electronic correlations[8,9].5d族过渡金属氧化物具有强自旋轨道耦合作用,可以衍生出诸多量子现象,例如,Sr2IrO4是强自旋轨道耦合导致的Mott绝缘体.为了研究Sr2IrO4新奇的电子结构和伴随的功能性,亟待调控其Mott能带.本文中,我们利用激光辅助分子束外延,在单晶SrTiO3衬底上外延制备了高质量的Sr2IrO4薄膜和Sr2IrO4/SrTiO3超晶格.电输运测试表明,热激发和Mott可变程跃迁两种传导机制分别适用于Sr2IrO4薄膜和Sr2IrO4/SrTiO3超晶格.这种传导机制的转变表明Sr2IrO4/SrTiO3界面电子结构发生了重构.此外,Sr2IrO4/SrTiO3超晶格的带隙从270.7–81.4meV的显著调控可能源自Ir–O–Ti界面电子去局域化导致的能带展宽.本研究表明,超晶格界面工程可在原子尺度上有效地调控强关联氧化物的电子结构.

关 键 词：自旋轨道耦合 量子现象 SRTIO3 过渡金属氧化物 强关联 超晶格 分子束外延 原子尺度 

分 类 号：O469[理学—凝聚态物理] TB383.2[理学—电子物理学]