Abstract
In iron-based superconductors the interactions driving the nematic order (that breaks four-fold rotational symmetry in the iron plane) may also mediate the Cooper pairing1. The experimental determination of these interactions, which are believed to depend on the orbital or the spin degrees of freedom1,2,3,4, is challenging because nematic order occurs at, or slightly above, the ordering temperature of a stripe magnetic phase1,5. Here, we study FeSe (ref. 6)—which exhibits a nematic (orthorhombic) phase transition at Ts = 90 K without antiferromagnetic ordering—by neutron scattering, finding substantial stripe spin fluctuations coupled with the nematicity that are enhanced abruptly on cooling through Ts. A sharp spin resonance develops in the superconducting state, whose energy (∼4 meV) is consistent with an electron–boson coupling mode revealed by scanning tunnelling spectroscopy7. The magnetic spectral weight in FeSe is found to be comparable to that of the iron arsenides8,9. Our results support recent theoretical proposals that both nematicity and superconductivity are driven by spin fluctuations1,10,11,12,13.
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Change history
15 December 2015
In the original version of this Letter published online, the x axis of Fig. 2a was labelled incorrectly. In addition, tick labels have been added to the x axes of Fig. 2b and Fig. 2d. This has been corrected in all versions of the Letter.
References
Fernandes, R. M., Chubukov, A. V. & Schmalian, J. What drives nematic order in iron-based superconductors? Nature Phys. 10, 97–104 (2014).
Fang, C., Yao, H., Tsai, W.-F., Hu, J. & Kivelson, S. A. Theory of electron nematic order in LaFeAsO. Phys. Rev. B 77, 224509 (2008).
Xu, C., Muller, M. & Sachdev, S. Ising and spin orders in the iron-based superconductors. Phys. Rev. B 78, 020501(R) (2008).
Kruger, F., Kumar, S., Zaanen, J. & van den Brink, J. Spin-orbital frustrations and anomalous metallic state in iron-pnictide superconductors. Phys. Rev. B 79, 054504 (2009).
Dai, P. C., Hu, J. P. & Dagotto, E. Magnetism and its microscopic origin in iron-based high-temperature superconductors. Nature Phys. 8, 709–718 (2012).
McQueen, T. M. et al. Tetragonal-to-orthorhombic structural phase transition at 90 K in the superconductor Fe1.01Se. Phys. Rev. Lett. 103, 057002 (2009).
Song, C. L. et al. Imaging the electron–boson coupling in superconducting FeSe films using a scanning tunneling microscope. Phys. Rev. Lett. 112, 057002 (2014).
Inosov, D. S. et al. Normal-state spin dynamics and temperature-dependent spin-resonance energy in optimally doped BaFe1.85Co0.15As2 . Nature Phys. 6, 178–181 (2010).
Zhao, J. et al. Effect of electron correlations on magnetic excitations in the isovalently doped iron-based superconductor Ba(Fe1−xRux)2As2 . Phys. Rev. Lett. 110, 147003 (2013).
Wang, F., Kivelson, S. & Lee, D. H. Nematicity and quantum paramagnetism in FeSe. Nature Phys. 11, 959–963 (2015).
Glasbrenner, J. K. et al. Effect of magnetic frustration on nematicity and superconductivity in iron chalcogenides. Nature Phys. 11, 953–958 (2015).
Yu, R. & Si, Q. M. Antiferroquadrupolar and Ising-nematic orders of a frustrated bilinear-biquadratic Heisenberg model and implications for the magnetism of FeSe. Phys. Rev. Lett. 115, 116401 (2015).
Scalapino, D. J. A common thread: The pairing interaction for unconventional superconductors. Rev. Mod. Phys. 84, 1383 (2012).
Chuang, T.-M. et al. Nematic electronic structure in the “parent” state of the iron-based superconductor Ca(Fe1−xCox)2 As2 . Science 327, 181–184 (2010).
Lu, X. Y. et al. Nematic spin correlations in the tetragonal state of uniaxial-strained BaFe2−xNixAs2 . Science 345, 657–660 (2014).
Yi, M. et al. Symmetry-breaking orbital anisotropy observed for detwinned Ba(Fe1−xCox)2As2 above the spin density wave transition. Proc. Natl Acad. Sci. USA 108, 6878–6883 (2011).
Chu, J.-H., Kuo, H.-H., Analytis, J. G. & Fisher, I. R. Divergent nematic susceptibility in an iron arsenide superconductor. Science 337, 710–712 (2012).
Zhang, Q. et al. Neutron-scattering measurements of the spin excitations in LaFeAsO and Ba(Fe0.953Co0.047)2As2: Evidence for a sharp enhancement of spin fluctuations by nematic order. Phys. Rev. Lett. 114, 057001 (2015).
Kontani, H. & Onari, S. Orbital-fluctuation-mediated superconductivity in iron pnictides: Analysis of the five-orbital Hubbard–Holstein model. Phys. Rev. Lett. 104, 157001 (2010).
Medvedev, S. 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).
Guo, J. G. et al. Superconductivity in the iron selenide KxFe2Se2(0 ≤ x ≤ 1.0). Phys. Rev. B 82, 180520(R) (2010).
Ge, J.-F. et al. Superconductivity above 100 K in single-layer FeSe films on doped SrTiO3 . Nature Mater. 14, 285–289 (2015).
Böhmer, A. E. et al. Origin of the tetragonal-to-orthorhombic phase transition in FeSe: A combined thermodynamic and NMR study of nematicity. Phys. Rev. Lett. 114, 027001 (2015).
Baek, S.-H. et al. Orbital-driven nematicity in FeSe. Nature Mater. 14, 210–214 (2015).
Xu, Z. J. et al. Local-moment magnetism in superconducting FeTe0.35Se0.65 as seen via inelastic neutron scattering. Phys. Rev. B 84, 052506 (2011).
Qiu, Y. M. et al. Spin gap and resonance at the nesting wave vector in superconducting FeSe0.4Te0.6 . Phys. Rev. Lett. 103, 067008 (2009).
Kasahara, S. et al. Field-induced superconducting phase of FeSe in the BCS-BEC cross-over. Proc. Natl Acad. Sci. USA 111, 16309–16313 (2014).
Zhang, C. L. et al. Distinguishing s± and s++ electron pairing symmetries by neutron spin resonance in superconducting NaFe0.935Co0.045As. Phys. Rev. B 88, 064504 (2013).
Park, J. T. et al. Magnetic resonant mode in the low-energy spin-excitation spectrum of superconducting Rb2Fe4Se5 single crystals. Phys. Rev. Lett. 107, 177005 (2011).
Chareev, D. et al. Single crystal growth and characterization of tetragonal FeSe1−x superconductors. Cryst. Eng. Commun. 15, 1989–1993 (2013).
Ma, M. W. et al. Flux-free growth of large superconducting crystal of FeSe by traveling-solvent floatingzone technique. Supercond. Sci. Technol. 27, 122001 (2014).
Hsu, F. C. et al. Superconductivity in the PbO-type structure α-FeSe. Proc. Natl Acad. Sci. USA 105, 14262–14264 (2008).
Rahn, M. C. et al. Strong (π, 0) spin fluctuations in β-FeSe observed by neutron spectroscopy. Phys. Rev. B 91, 180501 (2015).
Acknowledgements
We thank D. H. Lee, Q. Si, F. Wang and H. Yao for useful discussions. This work is supported by the National Natural Science Foundation of China (Grant No. 11374059), the Ministry of Science and Technology of China (973 project: 2015CB921302) and the Shanghai Pujiang Scholar Program (Grant No. 13PJ1401100). M.M. and F.Z. acknowledge support from the National Natural Science Foundation of China (Grant No. 11190020). H.C. received support from the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. A.N.V. was supported in part by the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST 〈MISiS〉 (No. 2-2014-036). D.A.C. and A.N.V. also acknowledge the support of the Russian Foundation for Basic Research through Grants 13-02-00174, 14-02-92002, 14-02-92693.
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J.Z. planned the project. M.M., F.Z., D.A.C. and A.N.V. synthesized the sample. Q.W., Y. Shen, B.P., Y.H., M.A.-H. and X.C. characterized the sample. Q.W. and Y. Shen. carried out the neutron experiments with experimental assistance from P.S., K.S., T.R.F., P.B., Y. Sidis and H.C. J.Z. and Q.W. analysed the data and wrote the paper. All authors provided comments for the paper.
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Wang, Q., Shen, Y., Pan, B. et al. Strong interplay between stripe spin fluctuations, nematicity and superconductivity in FeSe. Nature Mater 15, 159–163 (2016). https://doi.org/10.1038/nmat4492
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DOI: https://doi.org/10.1038/nmat4492
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