Tuning transport properties via rare-earth doping and epitaxial strain in Sr<sub>2</sub>IrO<sub>4</sub> thin films

ORAL

Abstract

Sr2IrO4 is predicted to be a candidate for high-temperature superconductivity upon carrier doping, whereas extensive research has proved it challenging to obtain a metallic phase in this compound, especially in thin films. Here, we explore the impact of stoichiometry on the crystallinity, as well as carrier doping and epitaxial strain on the transport properties of Sr2−xNdxIrO4 thin films. Via fine tuning the stoichiometry, the crystallinity of Sr2IrO4 films can be greatly enhanced, as indicated by the minimized systematic deviations of the x-ray diffraction peak positions. As the cation doping level increases, the resistivity of Sr2−xNdxIrO4 films decreases, but it remains semiconducting even at a high level of x = 0.4 where the resistivity has dropped by three orders of magnitude. By further applying compressive epitaxial strain, the Sr1.8Nd0.2IrO4 films exhibit a metallic-like behavior with an upturn at low temperature. Our finding reveals a promising combination of electron doping and compressive strain to narrow the band gap and tune the transport properties of iridate films for potential superconductivity.

*This work was supported by the National Key Projects for Research and Development of China (Grant No. 2022YFA1402502 and 2021YFA1400400), National Natural Science Foundation of China (Grant No. 11861161004), the Fundamental Research Funds for the Central Universities (Grant No. 0213-14380221), the Research Grants Council of Hong Kong (Grant No. N_PolyU531/18), and the Hong Kong Polytechnic University (Grant No. ZVRP). The STEM facility is funded by the Research Grants Council of Hong Kong (Grant No. C5029-18E).

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Publication: Jiangfeng Yang, Wei Guo, Zhihang Xu, Yuwei Liu, Haoying Sun, Wenjie Sun, Shengjun Yan, Yueying Li, Zhengbin Gu, Jian Zhou, Ye Zhu,* and Yuefeng Nie,† "Tuning transport properties via rare-earth doping and epitaxial strain in Sr2IrO4 thin films", Phys. Rev. B 107, 235152 (2023)

Presenters

  • Jiangfeng Yang

    • 1College of Engineering and Applied Sciences, Nanjing University 2Department of Materials Science and Engineering, University of Wisconsin-Madison

Authors

  • Jiangfeng Yang

    • 1College of Engineering and Applied Sciences, Nanjing University 2Department of Materials Science and Engineering, University of Wisconsin-Madison

  • Wei Guo

    • College of Engineering and Applied Sciences, Nanjing University

  • Zhihang Xu

    • Department of Applied Physics, The Hong Kong Polytechnic University

  • Yuwei Liu

    • College of Engineering and Applied Sciences, Nanjing University

  • Haoying Sun

    • College of Engineering and Applied Sciences, Nanjing University

  • Wenjie Sun

    • College of Engineering and Applied Sciences, Nanjing University

  • Shengjun Yan

    • College of Engineering and Applied Sciences, Nanjing University

  • Yueying Li

    • College of Engineering and Applied Sciences, Nanjing University

  • Zhengbin Gu

    • College of Engineering and Applied Sciences, Nanjing University

  • Jian Zhou

    • College of Engineering and Applied Sciences, Nanjing University

  • Ye Zhu

    • Department of Applied Physics, The Hong Kong Polytechnic University

  • Yuefeng Nie

    • College of Engineering and Applied Sciences, Nanjing University