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 ex...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℃ 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 5 d Sr2IrO4 epitaxial films, which could be extended to other Ruddlesden–Popper phases and potentially help the future study of exotic quantum phenomena in them.展开更多
基金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)+1 种基金Hefei Science Center-Chinese Academy of Sciences(Grant No.2016HSC-IU004)the support of the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2016389)
文摘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℃ 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 5 d Sr2IrO4 epitaxial films, which could be extended to other Ruddlesden–Popper phases and potentially help the future study of exotic quantum phenomena in them.
基金supported by the National Natural Science Foundation of China(12104007,12004366,12004367,51627901,12074212,and U19A2093)Tsinghua University-Zhejiang Deqing Joint Research Center for Materials Design and Industrial Innovation,Innovation Program for Quantum Science and Technology(2021ZD0302802)National Key R&D Program of the MOST of China(2022YFA1602603)。
