Coexistence of Superconductivity and Antiferromagnetism in (Li0.8Fe0.2) OHFeSe

Published

March 1, 2015

Author(s)

X. F. Lu, N. Z. Wang, Hui Wu, Y. P. Wu, D. Zhao, X. Z. Zeng, X. G. Luo, T. Wu, W. Bao, G. H. Zhang, F. Q. Huang, Qingzhen Huang, X. H. Chen

Abstract

FeSe-derived superconductors show some unique behaviors relative to iron-pnictide superconductors, which are very helpful to understand the mechanism of superconductivity in high-T_c iron-based superconductors. The low-energy electronic structure of the heavily electron-doped A_xFe₂Se₂ (A=K, Rb, Cs) deomonstrates that interband scattering or Fermi surface nesting is not a necessary ingredient for the unconventional superconductivity in iron-based superconductors. The superconducting transition temperature (T_c) in the one-unite-cell FeSe on SrTiO₃ substrate can reach as high as 65 K, largely transcending the bulk T_c of all known iron-based superconductors. However, in the case of A_xFe₂Se₂, the inter-grown antiferromagnetic insulating phase makes it difficult to study the underlying physics. Superconductors of alkali metal ions and NH₃ molecules or organic-molecules intercalated FeSe and single layer or thin film FeSe on SrTiO₃ substrate are extremely air-sensitive, which prevents the further investigation of their physical properties. Therefore, it is urgent to find a stable and accessible FeSe-derived superconductor for physical property measurements so as to study the underlying mechanism of superconductivity. Here, we report the air-stable superconductor (Li_0.8Fe_0.2)OHFeSe with high temperature superconductivity at 40 K synthesized by a novel hydrothermal method. The crystal structure is unambiguously determined by the combination of X-ray and neutron powder diffraction and nuclear magnetic resonance. It is also found that an antiferromagnetic order coexists with superconductivity in such new FeSe-derived superconductor. This novel synthetic route opens a new avenue for exploring other superconductors in the related systems. The combination of different structure characterization techniques helps to complementarily determine and understand the details of the complicated structures.

Citation

Nature Materials

Volume

14

Pub Type

Journals

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Keywords

FeSe-drived superconductor, Crystal Structure, Neutron diffraction, novel superconductor (Li0.8Fe0.2)OHFeSe

Citation

Lu, X. , Wang, N. , Wu, H. , Wu, Y. , Zhao, D. , Zeng, X. , Luo, X. , Wu, T. , Bao, W. , Zhang, G. , Huang, F. , Huang, Q. and Chen, X. (2015), Coexistence of Superconductivity and Antiferromagnetism in (Li_0.8Fe_0.2) OHFeSe, Nature Materials, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=917639 (Accessed October 9, 2025)