摘要
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270.7–81.4 meV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.
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Acknowledgements
Zhang J acknowledges the support from the National Key Research and Development Program of China (2016YFA0302300) and CAS Interdisciplinary Innovation Team. Zhang J also acknowledges the support from the National Natural Science Foundation of China (11974052), Beijing Natural Science Foundation (Z190008), and the beamline 1W1A of Beijing Synchrotron Radiation Facility.
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Author contributions Zhang J, Xiong C, Liu X and Yang Y conceived the experiments and prepared the manuscript. Liu X and Yang Y prepared the samples and performed the electronic transport and synchrotron XRD measurements. Shi Y and Yan D synthesized the target. Lu J performed the AFM measurement. Gu L and Zhang Q performed the STEM and EELS measurements. Cheng R and Wang F were involved in the discussion of the manuscript. All authors were involved in the revision of this manuscript.
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Xin Liu obtained his Bachelor’s degree in physics from China University of Mining and Technology in 2014. After that, he continued his education as a PhD candidate under the supervision of Prof. Jinxing Zhang at the Department of Physics, Beijing Normal University. His research interest focuses on the heterostructure and superlattice in correlated-electron oxide thin films.
Yuben Yang obtained his Bachelor’s degree in physics from the University of Science and Technology Beijing in 2017. After that, he continued his education as a PhD candidate under the supervision of Prof. Jinxing Zhang at the Department of Physics, Beijing Normal University. His research interest focuses on oxide thin films and heterostructures.
Changmin Xiong received his PhD degree in condensed matter physics in 2005 from the Institute of Physics, Chinese Academy of Sciences, China. Since 2009, he has been an associate professor at the Department of Physics, Beijing Normal University, China. His research focuses on the fabrication and understanding of the magnetic materials and complex oxides heterojunction.
Jinxing Zhang obtained his PhD degree from The Hong Kong Polytechnic University in 2009. In 2012, he joined the Department of Physics, Beijing Normal University as a professor. His team is striving to create a bridge between those fundamentally scientific discoveries in functional nano-systems and future possible applications such as sensing, actuation, data storage, energy conversion, quantum manipulation, etc.
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Liu, X., Yang, Y., Zhang, Q. et al. Mott gap engineering in Sr2IrO4/SrTiO3 superlattices. Sci. China Mater. 63, 1855–1860 (2020). https://doi.org/10.1007/s40843-020-1315-8
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DOI: https://doi.org/10.1007/s40843-020-1315-8