Review Article | Published:

What drives nematic order in iron-based superconductors?

Nature Physics volume 10, pages 97104 (2014) | Download Citation

Abstract

Although the existence of nematic order in iron-based superconductors is now a well-established experimental fact, its origin remains controversial. Nematic order breaks the discrete lattice rotational symmetry by making the x and y directions in the iron plane non-equivalent. This can happen because of a regular structural transition or as the result of an electronically driven instability — in particular, orbital order or spin-driven Ising-nematic order. The latter is a magnetic state that breaks rotational symmetry but preserves time-reversal symmetry. Symmetry dictates that the development of one of these orders immediately induces the other two, making the origin of nematicity a physics realization of the ‘chicken and egg problem’. In this Review, we argue that the evidence strongly points to an electronic mechanism of nematicity, placing nematic order in the class of correlation-driven electronic instabilities, like superconductivity and density-wave transitions. We discuss different microscopic models for nematicity and link them to the properties of the magnetic and superconducting states, providing a unified perspective on the phase diagram of the iron pnictides.

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Acknowledgements

We acknowledge useful discussions with E. Abrahams, J. Analytis, E. Bascones, A. Böhmer, J. van den Brink, P. Brydon, S. Bud’ko, P. Canfield, P. Chandra, P. Dai, M. Daghofer, L. Degiorgi, I. Eremin, I. Fisher, Y. Gallais, A. Goldman, A. Kaminski, J. Kang, V. Keppens, D. Khalyavin, M. Khodas, S. Kivelson, J. Knolle, H. Kontani, A. Kreyssig, F. Krüger, W. Ku, W.C. Lee, J. Lorenzana, W. Lv, S. Maiti, D. Mandrus, R. McQueeney, Y. Matsuda, I. Mazin, C. Meingast, A. Millis, P. Orth, R. Osborn, A. Pasupathy, I. Paul, P. Phillips, R. Prozorov, S. Sachdev, Q. Si, T. Shibauchi, L. Taillefer, M. Takigawa, M. Tanatar, M. Vavilov, P. Wölfle and M. Yoshizawa. The authors benefited much from discussions with our colleague Z. Tesanovic, who unexpectedly passed away last year. A.V.C. is supported by the Office of Basic Energy Sciences US Department of Energy under the grant #DE-FG02-ER46900. J.S. is supported by the Deutsche Forschungsgemeinschaft through DFG-SPP 1458 ‘Hochtemperatursupraleitung in Eisenpniktiden’.

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Affiliations

  1. School of Physics and Astronomy, University of MinnesotaMinneapolis Minnesota 55455 USA

    • R. M. Fernandes
  2. Department of Physics, University of Wisconsin-MadisonMadison Wisconsin 53706 USA

    • A. V. Chubukov
  3. Institut für Theorie der Kondensierten Materie, und Institut für Festkörperphysik, Karlsruher Institut für TechnologieKarlsruhe D-76131 Germany

    • J. Schmalian

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All authors were responsible for writing and revising the paper.

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The authors declare no competing financial interests.

Corresponding authors

Correspondence to R. M. Fernandes or A. V. Chubukov or J. Schmalian.

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https://doi.org/10.1038/nphys2877

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