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Coexistence of superconductivity and antiferromagnetism in (Li0.8Fe0.2)OHFeSe

Nature Materials volume 14, pages 325329 (2015) | Download Citation

Abstract

Iron selenide superconductors exhibit a number of unique characteristics that are helpful for understanding the mechanism of superconductivity in high-Tc iron-based superconductors more generally. However, in the case of AxFe2Se2 (A = K, Rb, Cs), the presence of an intergrown antiferromagnetic insulating phase makes the study of the underlying physics problematic. Moreover, FeSe-based systems intercalated with alkali metal ions, NH3 molecules or organic molecules are extremely sensitive to air, which prevents the further investigation of their physical properties. It is therefore desirable to find a stable and easily accessible FeSe-based superconductor to study its physical properties in detail. Here, we report the synthesis of an air-stable material, (Li0.8Fe0.2)OHFeSe, which remains superconducting at temperatures up to ~40 K, by means of a novel hydrothermal method. The crystal structure is unambiguously determined by a combination of X-ray and neutron powder diffraction and nuclear magnetic resonance. Moreover, antiferromagnetic order is shown to coexist with superconductivity. This synthetic route opens a path for exploring superconductivity in other related systems, and confirms the appeal of iron selenides as a platform for understanding superconductivity in iron pnictides more broadly.

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Acknowledgements

We would like to thank Z. Sun for discussions and Z. Qi for his help on infrared reflectance spectroscopy measurements. This work is supported by the National Natural Science Foundation of China (NSFC), the ‘Strategic Priority Research Program (B)’ of the Chinese Academy of Sciences, and the National Basic Research Program of China (973 Program). (Certain commercial suppliers are identified in this paper to foster understanding. Such identification does not imply recommendation or endorsement by the NIST).

Author information

Affiliations

  1. Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China

    • X. F. Lu
    • , N. Z. Wang
    • , Y. P. Wu
    • , D. Zhao
    • , X. Z. Zeng
    • , X. G. Luo
    • , T. Wu
    •  & X. H. Chen
  2. Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026, China

    • X. F. Lu
    • , N. Z. Wang
    • , Y. P. Wu
    • , D. Zhao
    • , X. Z. Zeng
    • , X. G. Luo
    • , T. Wu
    •  & X. H. Chen
  3. National Institute of Standards and Technology, Center for Neutron Research, 100 Bureau Dr., Gaithersburg Maryland 20878, USA

    • H. Wu
    •  & Q. Z. Huang
  4. Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA

    • H. Wu
  5. Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China

    • X. G. Luo
    • , T. Wu
    •  & X. H. Chen
  6. Department of Physics, Renmin University of China, Beijing 100872, China

    • W. Bao
  7. CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China

    • G. H. Zhang
    •  & F. Q. Huang
  8. Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China

    • G. H. Zhang
    •  & F. Q. Huang

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Contributions

X.F.L. and N.Z.W. contributed equally to this work. X.F.L. and N.Z.W. performed sample synthesis, composition determination, susceptibility, specific heat, X-ray diffraction and thermoelectric power measurements with assistance from X.Z.Z. and X.G.L., Q.Z.H., H.W. and W.B. performed NPD experiments and carried out the structure analysis. Y.P.W., D.Z. and T.W. performed NMR experiments and analysed data. G.H.Z. and F.Q.H. carried out the refinement on XRD. X.F.L., N.Z.W., Q.Z.H., T.W. and X.H.C. analysed the data and wrote the paper. X.H.C. conceived and coordinated the project, and is responsible for the infrastructure and project direction. All authors discussed the results and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to X. H. Chen.

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DOI

https://doi.org/10.1038/nmat4155

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