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Magnetic energy change available to superconducting condensation in optimally doped YBa2Cu3O6.95

Nature Physics volume 2, pages 600604 (2006) | Download Citation



Understanding the magnetic excitations in high-temperature (high-Tc) copper-oxide superconductors is important because they may mediate the electron pairing for superconductivity1,2. By determining the wavevector (Q) and energy (ħω) dependence of the magnetic excitations, it is possible to calculate the change in the exchange energy available to the superconducting condensation energy3,4,5. For the high-Tc superconductor YBa2Cu3O6+x, the most prominent feature in the magnetic excitations is the resonance6,7,8,9,10,11,12. Suggestions that the resonance contributes a major part of the superconducting condensation4,13 have not gained acceptance because the resonance is only a small portion of the total magnetic scattering12,13,14. Here, we report an extensive mapping of magnetic excitations for YBa2Cu3O6.95 (Tc93 K). Absolute intensity measurements of the full spectra allow us to estimate the change in the magnetic exchange energy between the normal and superconducting states, which is about 15 times larger than the superconducting condensation energy15,16—more than enough to provide the driving force for high-Tc superconductivity in YBa2Cu3O6.95.

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  1. 1.

    The case for dx2y2 pairing in the cuprate superconductors. Phys. Rep. 250, 330–365 (1995).

  2. 2.

    , & in The Physics of Superconductors, Vol I, Conventional and High-Tc Superconductors (eds Bennemann, K. H. & Ketterson, J. B.) 495–590 (Springer, Berlin, 2003).

  3. 3.

    & Superconducting condensation energy and an antiferromagnetic exchange-based pairing mechanism. Phys. Rev. B 58, 8222–8224 (1998).

  4. 4.

    & Quantitative test of a microscopic mechanism of high-temperature superconductivity. Nature 396, 733–735 (1998).

  5. 5.

    On the nature of pairing in the two-dimensional t–J model. Physica B 359–361, 512–514 (2005).

  6. 6.

    et al. Neutron scattering study of the YBa2Cu3O6+x system. Physica C 185, 86–92 (1991).

  7. 7.

    et al. Polarized neutron determination of the magnetic excitations in YBa2Cu3O7. Phys. Rev. Lett. 70, 3490–3493 (1993).

  8. 8.

    et al. Spin fluctuations in YBa2Cu3O6.6. Nature 395, 580–582 (1998).

  9. 9.

    et al. Spin susceptibility in underdoped YBa2Cu3O6+x. Phys. Rev. B 61, 14773–14786 (2000).

  10. 10.

    , , & Evolution of the resonance and incommensurate spin fluctuations in superconducting YBa2Cu3O6+x. Phys. Rev. B 63, 054525 (2001).

  11. 11.

    et al. From incommensurate to dispersive spin-fluctuations: The high-energy inelastic spectrum in superconducting YBa2Cu3O6.5. Phys. Rev. B 71, 024522 (2005).

  12. 12.

    , , , & The structure of the high-energy spin excitations in a high-transition-temperature superconductor. Nature 429, 531–534 (2004).

  13. 13.

    et al. The magnetic excitation spectrum and thermodynamics of high-Tc superconductors. Science 284, 1344–1347 (1999).

  14. 14.

    , & Spin-1 neutron resonance peak cannot account for electronic anomalies in the cuprate superconductors. Phys. Rev. Lett. 88, 257002 (2002).

  15. 15.

    , , & Specific heat evidence on the normal state pseudogap. J. Phys. Chem. Solids 59, 2091–2094 (1998).

  16. 16.

    et al. Evolution of the specific-heat anomaly of the high-temperature superconductor in YBa2Cu3O7 under the influence of doping through application of pressure up to 10 GPa. J. Phys. Condens. Matter 17, 4135–4145 (2005).

  17. 17.

    et al. Mapping spin-wave dispersions in stripe-ordered La2xSrxNiO4 (x=0.275,0.333). Phys. Rev. B 72, 064437 (2005).

  18. 18.

    et al. Dispersion of magnetic excitations in optimally doped superconducting YBa2Cu3O6.95. Phys. Rev. Lett. 93, 207003 (2004).

  19. 19.

    et al. Spin dynamics in the high-Tc superconducting system YBa2Cu3O6+x. Physica B 213/214, 48–53 (1995).

  20. 20.

    & Spin dynamics in a doped-Mott-insulator superconductor. Phys. Rev. B 71, 134516 (2005).

  21. 21.

    et al. High-frequency spin waves in YBa2Cu3O6.15. Phys. Rev. B 54, R6905–R6908 (1996).

  22. 22.

    et al. Direct observation of optical magnons in YBa2Cu3O6.2. Phys. Rev. B 53, R14741–R14744 (1996).

  23. 23.

    et al. Nodal quasiparticle lifetimes in cuprate superconductors. Phys. Rev. B 72, 214512 (2005).

  24. 24.

    et al. Resonant magnetic excitations at high energy in superconducting YBa2Cu3O6.85. Phys. Rev. Lett. 93, 167001 (2004).

  25. 25.

    et al. Two resonant magnetic modes in an overdoped high Tc superconductor. Phys. Rev. Lett. 91, 237002 (2003).

  26. 26.

    & Measuring condensate fraction in superconductors. Phys. Rev. B 61, 14821–14824 (2000).

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We thank E. Dagotto, Z. Y. Wen and F. C. Zhang for helpful discussions. This work is supported by the US DOE Office of Science, Division of Materials Science, Basic Energy Sciences under contract No. DE-FG02-05ER46202 (H.W. and P.D.). Oak Ridge National Laboratory is supported by the US DOE under contract No. DE-AC05-00OR22725 with UT/Battelle LLC. S.M.H. is supported by the UK EPSRC. D.J.S. would like to acknowledge the Center for Nanophase Material Science at Oak Ridge National Laboratory for their support.

Author information


  1. Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200, USA

    • Hyungje Woo
    •  & Pengcheng Dai
  2. Center for Neutron Scattering, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA

    • Hyungje Woo
    • , Pengcheng Dai
    •  & H. A. Mook
  3. H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, UK

    • S. M. Hayden
  4. Institut für Theoretische Physik, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany

    • T. Dahm
  5. Department of Physics, University of California, Santa Barbara, California 93106, USA

    • D. J. Scalapino
  6. ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK

    • T. G. Perring
  7. Department of Materials Science and Engineering, University of Missouri-Rolla, Rolla, Missouri 65409-0330, USA

    • F. Doğan


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Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Pengcheng Dai or H. A. Mook.

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