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Hidden magnetic excitation in the pseudogap phase of a high-Tc superconductor

Nature volume 468, pages 283285 (11 November 2010) | Download Citation


The elucidation of the pseudogap phenomenon of the high-transition-temperature (high-Tc) copper oxides—a set of anomalous physical properties below the characteristic temperature T* and above Tc—has been a major challenge in condensed matter physics for the past two decades1. Following initial indications of broken time-reversal symmetry in photoemission experiments2, recent polarized neutron diffraction work demonstrated the universal existence of an unusual magnetic order below T* (refs 3, 4). These findings have the profound implication that the pseudogap regime constitutes a genuine new phase of matter rather than a mere crossover phenomenon. They are furthermore consistent with a particular type of order involving circulating orbital currents, and with the notion that the phase diagram is controlled by a quantum critical point5. Here we report inelastic neutron scattering results for HgBa2CuO4+δ that reveal a fundamental collective magnetic mode associated with the unusual order, and which further support this picture. The mode’s intensity rises below the same temperature T* and its dispersion is weak, as expected for an Ising-like order parameter6. Its energy of 52–56 meV renders it a new candidate for the hitherto unexplained ubiquitous electron–boson coupling features observed in spectroscopic studies7,8,9,10.

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We thank T. H. Geballe, S. A. Kivelson, E. M. Motoyama and C. M. Varma for discussions. This work was supported by the US Department of Energy and the US National Science Foundation, and by the National Natural Science Foundation, China. Y.L. acknowledges support from the Alexander von Humboldt Foundation during the final stage of completing the manuscript.

Author information

Author notes

    • Yuan Li
    •  & N. Barišić

    Present addresses: Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany (Y.L.); Institute of Physics, Bijenicka cesta 46, 10 000 Zagreb, Croatia (N.B.).


  1. Department of Physics, Stanford University, Stanford, California 94305, USA

    • Yuan Li
  2. Laboratoire Léon Brillouin, CEA-CNRS, CEA-Saclay, 91191 Gif sur Yvette, France

    • V. Balédent
    • , Y. Sidis
    •  & P. Bourges
  3. School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA

    • G. Yu
    •  & M. Greven
  4. T.H. Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA

    • N. Barišić
    •  & X. Zhao
  5. 1. Physikalisches Institut, Universität Stuttgart, 70550 Stuttgart, Germany

    • N. Barišić
  6. Institut für Physikalische Chemie, Universität Göttingen, 37077 Göttingen, Germany

    • K. Hradil
  7. Forschungsneutronenquelle Heinz Maier-Leibnitz, 85747 Garching, Germany

    • R. A. Mole
  8. Institut Laue Langevin, 38042 Grenoble Cedex 9, France

    • P. Steffens
  9. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, China

    • X. Zhao


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M.G., P.B. and Y.L. planned the project. Y.L., V.B. and G.Y. performed the neutron scattering experiments. Y.L., N.B. and X.Z. characterized and prepared the samples. N.B. performed the resistivity measurements. P.S., R.A.M., K.H., Y.S. and P.B. were local contacts for the neutron scattering experiments. Y.L. and M.G. analysed the data and wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to M. Greven.

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    Supplementary Information

    This file contains a Supplementary Discussion in 9 sections, Supplementary Data, additional references and Supplementary Figures 1-8 with legends.

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