Skip to main content

Thank you for visiting nature.com. 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.

  • Article
  • Published:

A key role for unusual spin dynamics in ferropnictides

Abstract

The discovery of high-Tc ferropnictides introduced a new family of superconductors, and has already revealed a complicated and often contradictory picture of the structural and magnetic properties. An almost unprecedented sensitivity of the calculated magnetism and Fermi surface to structural details prevents correspondence to experiment. Experimental probes of the order parameter are in surprisingly strong disagreement, even considering the relative immaturity of the field. We outline various and seemingly contradictory evidence, both theoretical and experimental, and show it can be rectified by assuming a large-moment spin density wave, well defined but with magnetic twin and antiphase boundaries, dynamic on the experimental timescale. Under this assumption, calculations can accurately reproduce even very fine details of the structure, and a natural explanation for the temperature separation of structural and magnetic transitions is provided. Thus, our theory restores agreement between experiment and theory in crucial areas, making further cooperative progress possible on both fronts.

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

Access options

Buy this article

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

Figure 1: Representative ferropnictide in-plane magnetic domains.

Similar content being viewed by others

References

  1. Lee, P. A., Nagaosa, N. & Wen, X.-G. Doping a Mott insulator: Physics of high-temperature superconductivity. Rev. Mod. Phys. 78, 17–85 (2006).

    Article  ADS  Google Scholar 

  2. Kamihara, Y., Watanabe, T., Hirano, M. & Hosono, H. Iron-based layered superconductor La[O1−xFx]FeAs (x=0.05–0.12) with Tc=26 K. J. Am. Chem. Soc. 130, 3296–3297 (2008).

    Article  Google Scholar 

  3. Gonnelli, R. S. et al. Coexistence of two order parameters and a pseudogap in the iron-based superconductor LaFeAsO1−xFx. Preprint at <http://arxiv.org/abs/0807.3149>.

  4. Szabó, P. et al. Evidence for two-gap superconductivity and SDW pseudogap in (Ba,K)Fe2As2 by directional point contact Andreev reflection spectroscopy. Preprint at <http://arxiv.org/abs/0809.1566>.

  5. Malone, L. et al. Magnetic penetration depth of single crystal SmFeAsO1−xFy: A fully gapped superconducting state. Preprint at <http://arxiv.org/abs/0806.3908>.

  6. Martin, C. et al. Nodeless superconducting gap in NdFeAsO0.9F0.1 single crystals from anisotropic penetration depth studies. Preprint at <http://arxiv.org/abs/0807.0876>.

  7. Ren, C. et al. Evidence for two gaps and breakdown of the Uemura plot in Ba0.6K0.4Fe2As2 single crystals. Preprint at <http://arxiv.org/abs/0808.0805>.

  8. Ding, H. et al. Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2 . Europhys. Lett. 83, 47001 (2008).

    Article  ADS  Google Scholar 

  9. Zhao, L. et al. Unusual superconducting gap in (Ba,K)Fe2As2 superconductor. Chin. Phys. Lett. 25, 4402–4405 (2008).

    Article  ADS  Google Scholar 

  10. Kondo, T. et al. Momentum dependence of the superconducting gap in NdFeAsO0:9F0:1 single crystals measured by angle resolved photoemission spectroscopy. Phys. Rev. Lett. 101, 147003 (2008).

    Article  ADS  Google Scholar 

  11. Evtushinsky, D. V. et al. Momentum dependence of the superconducting gap in Ba1−xKxFe2As2. Preprint at <http://arxiv.org/abs/0809.4455.

  12. Mazin, I. I. et al. The challenge of unravelling magnetic properties in ferropnictides. Phys. Rev. B 78, 085104 (2008).

    Article  ADS  Google Scholar 

  13. Yin, Z. P. et al. Electron–hole symmetry and magnetic coupling in antiferromagnetic LaOFeAs. Phys. Rev. Lett. 101, 047001 (2008).

    Article  ADS  Google Scholar 

  14. Yildirim, T. Origin of the 150 K anomaly in LaOFeAs; competing antiferromagnetic superexchange interactions, frustration, and structural phase transition. Phys. Rev. Lett. 101, 057010 (2008).

    Article  ADS  Google Scholar 

  15. Singh, D. J. & Du, M. H. Density functional study of LaFeAsO1−xFx: A low carrier density superconductor near itinerant magnetism. Phys. Rev. Lett. 100, 237003 (2008).

    Article  ADS  Google Scholar 

  16. Haule, K., Shim, J. H. & Kotliar, G. Correlated electronic structure of LaO1−xFxFeAs. Phys. Rev. Lett. 100, 226402 (2008).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  18. McGuire, M. A. et al. Phase transitions in LaFeAsO: structural, magnetic, elastic, and transport properties, heat capacity and Mössbauer spectra. Phys. Rev. B78, 094517 (2008).

    Article  ADS  Google Scholar 

  19. Koda, A. et al. J. Phys. Condens. Matter 17, L257–L264 (2005).

    Article  Google Scholar 

  20. Rotter, M. et al. Superconductivity at 38 K in the iron arsenide (Ba1−xKx)Fe2As2 . Phys. Rev. Lett. 101, 107006 (2008).

    Article  ADS  Google Scholar 

  21. Klauss, H.–H. et al. Commensurate spin density wave in LaOFeAs: A local probe study. Phys. Rev. Lett. 101, 077005 (2008).

    Article  ADS  Google Scholar 

  22. Chen, Y. et al. Magnetic order of the iron spins in NdOFeAs. Phys. Rev. B 78, 064515 (2008).

    Article  ADS  Google Scholar 

  23. Qiu, Y. et al. Structure and magnetic order in the NdFeAs(O,F) superconductor system. Preprint at <http://arxiv.org/abs/0806.2195>.

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

    Article  ADS  Google Scholar 

  25. Chen, G. F. et al. Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO1−xFxFeAs. Phys. Rev. Lett. 100, 247002 (2008).

    Article  ADS  Google Scholar 

  26. Huang, Q. et al. Magnetic order in BaFe2As2, the parent compound of the FeAs based superconductors in a new structural family. Preprint at <http://arxiv.org/abs/0806.2776>.

  27. Aczel, A. A. Muon spin relaxation studies of magnetic order and superfluid density in antiferromagnetic NdOFeAs, BaFe2As2 and superconducting (Ba,K)Fe2As2. Preprint at <http://arxiv.org/abs/0807.1044>.

  28. Wang, X. F. et al. Growth and anisotropy in transport properties and susceptibility of single crystals BaFe2As2. Preprint at <http://arxiv.org/abs/0806.2452>.

  29. Sefat, A. S. et al. Electronic correlations in the superconductor LaFeAsO0.89F0.11 with low carrier density. Phys. Rev. B 77, 174503 (2008).

    Article  ADS  Google Scholar 

  30. Pinsard-Gaudart, L., Berardan, D., Bobroff, J. & Dragoe, N. Large Seebeck coefficients in iron-oxypnictides: A new route towards n-type thermoelectric materials. Phys. Status Solidi-Rapid Res. Lett. 2, 185–187 (2008).

    Article  ADS  Google Scholar 

  31. Kreyssig, A. et al. Pressure-induced volume-collapsed tetragonal phase of CaFe2As2 as seen via neutron scattering. Phys. Rev. B 78, 184517 (2008).

    Article  ADS  Google Scholar 

  32. Park, T. et al. Pressure-induced superconductivity in single crystal CaFe2As2 . J. Phys. Condens. Matter 20, 322204 (2008).

    Article  Google Scholar 

  33. Alireza, P. et al. Superconductivity up to 29 K in SrFe2As2 and BaFe2As2 at high pressures. Preprint at <http://arxiv.org/abs/0807.1896>.

  34. Pulikkoti, J. J., van Schilfgaarde, M. & Antropov, M. P. Competition between antiferromagnetic instability and frustrations in Fe–Se. Preprint at <http://arxiv.org/abs/0809.0283>.

  35. Yildirim, T. The unprecedented giant coupling of Fe-spin state and the As–As hybridization in iron-pnictide. Preprint at <http://arxiv.org/abs/0807.3936>.

  36. Fukuda, T. et al. Lattice dynamics of LaFeAsO1−xFx and PrFeAsO1−y via inelastic X-ray scattering and first-principles calculation. J. Phys. Soc. Japan 77, 103715 (2008).

    Article  ADS  Google Scholar 

  37. Zhao, J. et al. Spin and lattice structure of single crystal SrFe2As2 . Phys. Rev. B 78, 140504 (2008).

    Article  ADS  Google Scholar 

  38. Jesche, A. et al. Strong coupling between magnetic and structural order parameters in SrFe2As2 . Phys. Rev. B 78, 180504 (2008).

    Article  ADS  Google Scholar 

  39. Ishibashi, S., Terakura, K. & Hosono, H. A possible ground state and its electronic structure of a mother material (LaOFeAs) of new superconductors. J. Phys. Soc. Japan. 77, 053709 (2008).

    Article  ADS  Google Scholar 

  40. Garcia, D. R. et al. Core level and valence band study of LaO0.9F0.1FeAs. Preprint at <http://arxiv.org/abs/0810.3034>.

  41. Bondino, F. et al. Evidence for strong itinerant spin fluctuations in the normal state of CeFeAsO(0.89)F(0.11) iron oxypnictides. Phys. Rev. Lett. (in the press).

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to M. D. Johannes.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Mazin, I., Johannes, M. A key role for unusual spin dynamics in ferropnictides. Nature Phys 5, 141–145 (2009). https://doi.org/10.1038/nphys1160

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nphys1160

This article is cited by

Search

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