Abstract

Pressure has an essential role in the production1 and control2,3 of superconductivity in iron-based superconductors. Substitution of a large cation by a smaller rare-earth ion to simulate the pressure effect has raised the superconducting transition temperature Tc to a record high of 55 K in these materials4,5. In the same way as Tc exhibits a bell-shaped curve of dependence on chemical doping, pressure-tuned Tc typically drops monotonically after passing the optimal pressure1,2,3. Here we report that in the superconducting iron chalcogenides, a second superconducting phase suddenly re-emerges above 11.5 GPa, after the Tc drops from the first maximum of 32 K at 1 GPa. The Tc of the re-emerging superconducting phase is considerably higher than the first maximum, reaching 48.0–48.7 K for Tl0.6Rb0.4Fe1.67Se2, K0.8Fe1.7Se2 and K0.8Fe1.78Se2.

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References

  1. 1.

    , , & Pressure induced superconductivity in CaFe2As2. Phys. Rev. Lett. 101, 057006 (2008)

  2. 2.

    et al. Superconductivity at 43 K in an iron-based layered compound LaO1-xFxFeAs. Nature 453, 376–378 (2008)

  3. 3.

    et al. Electronic and magnetic phase diagram of β-Fe1.01Se with superconductivity at 36.7 K under pressure. Nature Mater. 8, 630–633 (2009)

  4. 4.

    et al. Superconductivity at 43 K in SmFeAsO1−xFx. Nature 453, 761–762 (2008)

  5. 5.

    et al. Superconductivity at 55 K in iron-based F-doped layered quaternary compound Sm[O1-xFx]FeAs. Chin. Phys. Lett. 25, 2215–2216 (2008)

  6. 6.

    et al. Superconductivity in the iron selenide KxFe2Se2 (0<x1.0). Phys. Rev. B 82, 180520(R) (2010)

  7. 7.

    et al. Synthesis and crystal growth of Cs0.8(FeSe0.98)2: a new iron-based superconductor with TC = 27 K. J. Phys. Condens. Matter 23, 052203 (2011)

  8. 8.

    et al. Superconductivity at 32 K in single-crystalline RbxFe2-ySe2. Phys. Rev. B 83, 060512(R) (2011)

  9. 9.

    et al. Fe-based superconductivity with TC = 31 K bordering an antiferromagnetic insulator in (TI,K)FexSe2. Europhys. Lett. 94, 27009 (2011)

  10. 10.

    Iron superconductivity weathers another storm. Physics 4, 26 (2011)

  11. 11.

    et al. A novel large moment antifarromagnetic order in K0.8Fe1.6Se2 superconductor. Chin. Phys. Lett. 28, 086104 (2011)

  12. 12.

    et al. Observation of two distinct superconducting phases in CeCu2Si2. Science 302, 2104–2107 (2003)

  13. 13.

    et al. Enhancement of superconductivity by pressure-driven competition in electronic order. Nature 466, 950–953 (2010)

  14. 14.

    et al. Magnetic-field-induced superconductivity in a two-dimensional organic conductor. Nature 410, 908–910 (2001)

  15. 15.

    , , & Link between spin fluctuations and electron pairing in copper oxide superconductors. Nature 476, 73–75 (2011)

  16. 16.

    , , & The effect of varying Fe-content on transport properties of K intercalated iron selenide KxFe2−ySe2. Phys. Rev. B 83, 132502 (2011)

  17. 17.

    et al. Superconductivity at 32 K and anisotropy in Tl0.58Rb0.42Fe1.72Se2 crystals. Europhys. Lett. 93, 47004 (2011)

  18. 18.

    et al. High-pressure studies of doped-type organic superconductors. J. Phys. Soc. Jpn 76 (Suppl. A). 188–189 (2007)

  19. 19.

    & Heavy fermions and quantum phase transitions. Science 329, 1161–1166 (2010)

  20. 20.

    , & Calibration of the ruby pressure gauge to 800 Kbar under quasi-hydrostatic conditions. J. Geophys. Res. 91, 4673–4676 (1986)

  21. 21.

    , , & Pressure-induced superconducting state of europium metal at low temperatures. Phys. Rev. Lett. 102, 197002 (2009)

Download references

Acknowledgements

We thank I. I. Mazin, W. Bao, and T. Xiang for discussions and J. S. Schilling for the help with the alternating-current susceptibility technique. This work in China was supported by the NSCF, 973 projects, and Chinese Academy of Sciences. This work in the USA was supported as part of the EFree, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences (DOE-BES). The High Pressure Collaborative Access Team (HPCAT) is supported by CIW, CDAC, UNLV and LLNL through funding from the DOE-NNSA, the DOE-BES and the NSF. The Advanced Photon Source (APS) is supported by the DOE-BES.

Author information

Author notes

    • Liling Sun
    •  & Xiao-Jia Chen

    These authors contributed equally to this work.

Affiliations

  1. Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China

    • Liling Sun
    • , Jing Guo
    • , Peiwen Gao
    • , Xiaolong Chen
    • , Genfu Chen
    • , Qi Wu
    • , Chao Zhang
    • , Dachun Gu
    • , Xiaoli Dong
    • , Xi Dai
    •  & Zhongxian Zhao
  2. Geophysical Laboratory, Carnegie Institution of Washington, Washington DC 20015, USA

    • Xiao-Jia Chen
    •  & Ho-kwang Mao
  3. Department of Physics, South China University of Technology, Guangzhou 510640, China

    • Xiao-Jia Chen
  4. NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA

    • Qing-Zhen Huang
  5. Department of Physics, Zhejiang University, Hangzhou 310027, China

    • Hangdong Wang
    •  & Minghu Fang
  6. HPSynC, Geophysical Laboratory, Carnegie Institution of Washington, 9700 South Cass Avenue, Argonne, Illinois 60439, USA

    • Lin Wang
  7. Shanghai Synchrotron Radiation Facilities, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China

    • Ke Yang
    •  & Aiguo Li

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Contributions

L.S., X.-J.C., H.M. and Z.Z. designed the project; X.-J.C., L.S., H.M., Q.W. and Z.Z. wrote the paper; P.G., J.G., C.Z. and L.S. performed the resistance and magnetic susceptibility measurements; X.-J.C., L.W., J.G., P.G., L.S., K.Y. and A.L. performed synchrotron X-ray diffraction measurements; and M.F., X.C. and G.C. synthesized the single crystals. All the authors analysed the data and discussed the results. All the authors read and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Ho-kwang Mao or Zhongxian Zhao.

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    Supplementary Information

    This file contains Supplementary Text, Supplementary Figures 1-2 with legends and Supplementary Tables 1-4.

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DOI

https://doi.org/10.1038/nature10813

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