中国物理B ›› 2019, Vol. 28 ›› Issue (7): 78102-078102.doi: 10.1088/1674-1056/28/7/078102

• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇    下一篇

Growth of high quality Sr2IrO4 epitaxial thin films onconductive substrates

Hui Xu(徐珲), Zhangzhang Cui(崔璋璋), Xiaofang Zhai(翟晓芳), Yalin Lu(陆亚林)   

  1. 1 Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China;
    2 National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China;
    3 Synergy Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China;
    4 Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
  • 收稿日期:2019-02-18 修回日期:2019-04-01 出版日期:2019-07-05 发布日期:2019-07-05
  • 通讯作者: Xiaofang Zhai, Yalin Lu E-mail:xfzhai@ustc.edu.cn;yllu@ustc.edu.cn
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 51627901 and 11574287), the National Key Research and Development Program of China (Grant No. 2016YFA0401004), and Hefei Science Center-Chinese Academy of Sciences (Grant No. 2016HSC-IU004). X. Z. acknowledges the support of the Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2016389).

Growth of high quality Sr2IrO4 epitaxial thin films onconductive substrates

Hui Xu(徐珲)1, Zhangzhang Cui(崔璋璋)1,2, Xiaofang Zhai(翟晓芳)1,3, Yalin Lu(陆亚林)1,2,4   

  1. 1 Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China;
    2 National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China;
    3 Synergy Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China;
    4 Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
  • Received:2019-02-18 Revised:2019-04-01 Online:2019-07-05 Published:2019-07-05
  • Contact: Xiaofang Zhai, Yalin Lu E-mail:xfzhai@ustc.edu.cn;yllu@ustc.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 51627901 and 11574287), the National Key Research and Development Program of China (Grant No. 2016YFA0401004), and Hefei Science Center-Chinese Academy of Sciences (Grant No. 2016HSC-IU004). X. Z. acknowledges the support of the Youth Innovation Promotion Association of Chinese Academy of Sciences (Grant No. 2016389).

摘要:

Ruddlesden-Popper iridium oxides have attracted considerable interest because of the many proposed novel quantum states that arise from the large spin-orbit coupling of the heavy iridium atoms in them. A prominent example is the single layer Sr2IrO4, in which superconductivity has been proposed under electron doping. However, the synthesis of Sr2IrO4 high quality thin films has been a huge challenge due to the easy formation of impurities associated with different numbers of SrO layers. Thus techniques to optimize the growth of pure phase Sr2IrO4 are urgently required. Here we report the deposition of high quality Sr2IrO4 thin films on both insulating SrTiO3 and conducting SrTiO3:Nb substrates using pulsed laser deposition assisted with reflective high-energy electron diffraction. The optimal deposition temperature of Sr2IrO4 epitaxial films on SrTiO3:Nb substrates is about 90 °C lower than that on SrTiO3 substrates. The electrical transports of high quality Sr2IrO4 films are measured, which follow the three-dimensional Mott variable-range hopping model. The film magnetizations are measured, which show weak ferromagnetism below~240 K with a saturation magnetization of~0.2 μB/Ir at 5 K. This study provides applicable methods to prepare high quality 5d Sr2IrO4 epitaxial films, which could be extended to other Ruddlesden-Popper phases and potentially help the future study of exotic quantum phenomena in them.

关键词: substrates, pulsed laser deposition, iridates, conduction mechanism

Abstract:

Ruddlesden-Popper iridium oxides have attracted considerable interest because of the many proposed novel quantum states that arise from the large spin-orbit coupling of the heavy iridium atoms in them. A prominent example is the single layer Sr2IrO4, in which superconductivity has been proposed under electron doping. However, the synthesis of Sr2IrO4 high quality thin films has been a huge challenge due to the easy formation of impurities associated with different numbers of SrO layers. Thus techniques to optimize the growth of pure phase Sr2IrO4 are urgently required. Here we report the deposition of high quality Sr2IrO4 thin films on both insulating SrTiO3 and conducting SrTiO3:Nb substrates using pulsed laser deposition assisted with reflective high-energy electron diffraction. The optimal deposition temperature of Sr2IrO4 epitaxial films on SrTiO3:Nb substrates is about 90 °C lower than that on SrTiO3 substrates. The electrical transports of high quality Sr2IrO4 films are measured, which follow the three-dimensional Mott variable-range hopping model. The film magnetizations are measured, which show weak ferromagnetism below~240 K with a saturation magnetization of~0.2 μB/Ir at 5 K. This study provides applicable methods to prepare high quality 5d Sr2IrO4 epitaxial films, which could be extended to other Ruddlesden-Popper phases and potentially help the future study of exotic quantum phenomena in them.

Key words: substrates, pulsed laser deposition, iridates, conduction mechanism

中图分类号:  (Methods of deposition of films and coatings; film growth and epitaxy)

  • 81.15.-z
61.05.jh (Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)) 71.70.Ej (Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect) 71.27.+a (Strongly correlated electron systems; heavy fermions)