Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Electronic and magnetic phase diagram of β-Fe1.01Se with superconductivity at 36.7 K under pressure


The discovery of new high-temperature superconductors1 based on FeAs has led to a new ‘gold rush’ in high-TC superconductivity. All of the new superconductors share the same common structural motif of FeAs layers and reach TC values up to 55 K (ref. 2). Recently, superconductivity has been reported in FeSe (ref. 3), which has the same iron pnictide layer structure, but without separating layers. Here, we report the magnetic and electronic phase diagram of β-Fe1.01Se as a function of temperature and pressure. The superconducting transition temperature increases from 8.5 to 36.7 K under an applied pressure of 8.9 GPa. It then decreases at higher pressures. A marked change in volume is observed at the same time as TC rises, owing to a collapse of the separation between the Fe2Se2 layers. No static magnetic ordering is observed for the whole pT phase diagram. We also report that at higher pressures (starting around 7 GPa and completed at 38 GPa), Fe1.01Se transforms to a hexagonal NiAs-type structure and exhibits non-magnetic behaviour.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Figure 1: Structural behaviour of Fe1.01Se under pressure.
Figure 2: Resistivity and Mössbauer measurements under pressure.
Figure 3: Electronic phase diagram of Fe1.01Se as a function of pressure.


  1. Kamihara, Y. J., Watanabe, T., Hirano, M. & Hosono, H. Iron-based layered superconductor La[O1−xFx]FeAs with TC=26 K. J. Am. Chem. Soc. 130, 3296–3297 (2008).

    Article  CAS  Google Scholar 

  2. Ren, Z. A. 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).

    Article  CAS  Google Scholar 

  3. Hsu, F. C. et al. Superconductivity in the PbO-type structure alpha-FeSe. Proc. Natl Acad. Sci. 105, 14262–14264 (2008).

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

  5. Zhao, J. et al. Structural and magnetic phase diagram of CeFeAsO1−xFx and its relation to high-temperature superconductivity. Nature Mater. 7, 953–959 (2008).

    Article  CAS  Google Scholar 

  6. Rotter, M., Tegel, M. & Johrendt, D. Superconductivity at 38 K in the iron arsenide Ba1−xKxFe2As2 . Phys. Rev. Lett. 101, 107006 (2008).

    Article  Google Scholar 

  7. Pitcher, M. J. et al. Structure and superconductivity of LiFeAs. Chem. Commun. 45, 5918–5920 (2008).

    Article  Google Scholar 

  8. Takagi, H. et al. Systematic evolution of temperature-dependent resistivity in La2−xSrxCuO4 . Phys. Rev. Lett. 69, 2975–2978 (1992).

    Article  CAS  Google Scholar 

  9. Ando, Y. et al. Electronic phase diagram of high-Tc cuprate superconductors from a mapping of the In-plane resistivity curvature. Phys. Rev. Lett. 93, 267001 (2004).

    Article  Google Scholar 

  10. Mizuguchi, Y., Tomioka, F., Tsuda, S., Yamaguchi, T. & Takano, Y. Superconductivity at 27 K in tetragonal FeSe under high pressure. Appl. Phys. Lett. 93, 152505 (2008).

    Article  Google Scholar 

  11. McQueen, T. M. et al. Extreme sensitivity of superconductivity to stoichiometry in FeSe (Fe1+δSe). Phys. Rev. B 79, 014522 (2009).

    Article  Google Scholar 

  12. Millican, J. N., Phelan, D., Thomas, E. L., Leao, J. B. & Carpenter, E. Pressure-induced effects on the structure of the FeSe superconductor. Solid. State Commun. 149, 707–710 (2009).

    Article  CAS  Google Scholar 

  13. Medvedev, S. et al. Superconductivity at 36 K in beta-Fe1.01Se with the compression of the interlayer separation under pressure. Preprint at <> (2009).

  14. Imai, T., Ahilan, K., Ning, F. L., McQueen, T. M. & Cava, R. J. Why does undoped FeSe become a high Tc superconductor under pressure? Phys. Rev. Lett. 102, 177005 (2009).

    Article  CAS  Google Scholar 

  15. Lee, K.-W., Pardo, V. & Pickett, W. E. Magnetism driven by anion vacancies in superconducting αFeSe1−x . Phys. Rev. B 78, 174502 (2008).

    Article  Google Scholar 

  16. Ok, H. N. & Lee, S. W. Mössbauer study of ferrimagnetic Fe7Se8 . Phys. Rev. B 8, 4267–4269 (1973).

    Article  CAS  Google Scholar 

  17. Srivastava, M. M. & Srivastava, O. N. Studies of structural transformations and electrical behaviour of FeSe films. Thin Solid Films 29, 275–284 (1975).

    Article  Google Scholar 

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

    Article  CAS  Google Scholar 

  19. Reddy, K. V. & Chetty, S. C. Mössbauer studies on the Fe–Se systems. Phys. Status. Solidi A 32, 585–592 (1975).

    Article  CAS  Google Scholar 

  20. Subedi, A., Zhang, L. J., Singh, D. J. & Du, M. H. Density functional study of FeS, FeSe, and FeTe: Electronic structure, magnetism, phonons, and superconductivity. Phys. Rev. B 78, 134514 (2008).

    Article  Google Scholar 

  21. Zhang, L. J., Singh, D. J. & Du, M. H. Density functional study of excess Fe in Fe1+xTe: Magnetism and doping. Phys. Rev. B 79, 012506 (2009).

    Article  Google Scholar 

  22. Hess, C. et al. The intrinsic electronic phase diagram of iron-pnictide superconductors. Preprint at <> (2008).

  23. Luetkens, H. et al. The electronic phase diagram of the LaO1−xFxFeAs superconductor. Nature Mater. 8, 305–309 (2009).

    Article  CAS  Google Scholar 

  24. Cruz, C. et al. Magnetic order close to superconductivity in the iron-based layered LaO1−xFxFeAs systems. Nature 453, 899–902 (2008).

    Article  Google Scholar 

  25. Drew, A. J. et al. Coexistence of static magnetism and superconductivity in SmFeAsO1−xFx as revealed by muon spin rotation. Nature Mater. 10.1038/NMAT2397 (2009).

  26. Lynn, J. W. & Dai, P. Neutron studies of the iron-based family of high TC magnetic superconductors. Physica C 469, 469–476 (2009).

    Article  CAS  Google Scholar 

  27. Margadonna, S. et al. Pressure evolution of low-temperature crystal structure and bonding of 37 K Tc FeSe superconductor. Preprint at <> (2009).

  28. Eremets, M. I. et al. Superconductivity in boron. Science 293, 272–274 (2001).

    Article  CAS  Google Scholar 

Download references


The work at Mainz was financially supported by the DFG in the Collaborative Research Center Condensed Matter Systems with Variable Many-Body Interactions (TRR 49). The work at Princeton was supported primarily by the US Department of Energy, Division of Basic Energy Sciences, Grant No. DE-FG02-98ER45706. T.M.M. gratefully acknowledges the support of the National Science Foundation Graduate Research Foundation program. I.T. was partly supported by the Russian Research Foundation under grant No. 08-02-00897a and by the Presidium of RAS under grant No. 27-4.1.10. We are grateful to V. Prakapenka for XRD measurements at GeoSoilEnviroCARS (sector 13, APS) at Argonne National Laboratory.

Author information

Authors and Affiliations



All authors contributed equally to the work presented in this letter.

Corresponding author

Correspondence to C. Felser.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Medvedev, S., McQueen, T., Troyan, I. 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).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing