Interplay of magnetism and high-Tc superconductivity at individual Ni impurity atoms in Bi2Sr2CaCu2O8+δ

Abstract

Magnetic interactions and magnetic impurities are destructive to superconductivity in conventional superconductors1. By contrast, in some unconventional macroscopic quantum systems (such as superfluid 3He and superconducting UGe2), the superconductivity (or superfluidity) is actually mediated by magnetic interactions. A magnetic mechanism has also been proposed for high-temperature superconductivity2,3,4,5,6. Within this context, the fact that magnetic Ni impurity atoms have a weaker effect on superconductivity than non-magnetic Zn atoms in the high-Tc superconductors has been put forward as evidence supporting a magnetic mechanism5,6. Here we use scanning tunnelling microscopy to determine directly the influence of individual Ni atoms on the local electronic structure of Bi2Sr2CaCu2O8+δ. At each Ni site we observe two d-wave impurity states7,8 of apparently opposite spin polarization, whose existence indicates that Ni retains a magnetic moment in the superconducting state. However, analysis of the impurity-state energies shows that quasiparticle scattering at Ni is predominantly non-magnetic. Furthermore, we show that the superconducting energy gap and correlations are unimpaired at Ni. This is in strong contrast to the effects of non-magnetic Zn impurities, which locally destroy superconductivity9. These results are consistent with predictions for impurity atom phenomena5,6 derived from a magnetic mechanism.

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Figure 1: Maps of the local density of electronic states at energies E = ±9 meV, revealing the locations of the Ni impurity states.
Figure 2: Detailed spatial structure of the impurity state at a single Ni atom.
Figure 3: Differential conductance spectra above the Ni atom and at several nearby locations.
Figure 4: Evolution of the dI/dV spectra and superconducting energy gap as a function of distance from the Ni atom.

References

  1. 1

    Abrikosov, A. A. & Gorkov, L. P. Contribution to the theory of superconducting alloys with paramagnetic impurities. Sov. Phys. JETP 12, 1243–1253 (1961).

    Google Scholar 

  2. 2

    Monthoux, P., Balatsky, A. V. & Pines, D. Weak-coupling theory of high-temperature superconductivity in the antiferromagnetically correlated copper oxides. Phys. Rev. B 46, 14803–14817 (1992).

    ADS  CAS  Article  Google Scholar 

  3. 3

    Moriya, T., Takehashi, Y. & Ueda, K. Antiferromagnetic spin fluctuations and superconductivity in two-dimensional metals - a possible model for high TC oxides. J. Phys. Soc. Jpn 59, 2905–2915 (1990).

    ADS  CAS  Article  Google Scholar 

  4. 4

    Bickers, N. E., Scalapino, D. J. & White, S. R. Conserving approximations for strongly correlated electron systems: Bethe-Salpeter equation and dynamics for the two-dimensional Hubbard model. Phys. Rev. Lett. 62, 961–964 (1989).

    ADS  CAS  Article  Google Scholar 

  5. 5

    Monthoux, P. & Pines, D. Spin-fluctuation-induced superconductivity and normal-state properties of YBa2Cu3O7. Phys. Rev. B 49, 4261–4278 (1994).

    ADS  CAS  Article  Google Scholar 

  6. 6

    Pines, D. Understanding high temperature superconductors: progress and prospects. Physica C 282–287, 273–278 (1997).

    ADS  Article  Google Scholar 

  7. 7

    Balatsky, A. V., Salkola, M. I. & Rosengren, A. Impurity-induced virtual bound states in d-wave superconductors. Phys. Rev. B 51, 15547–15551 (1995).

    ADS  CAS  Article  Google Scholar 

  8. 8

    Salkola, M. I., Balatsky, A. V. & Schrieffer, J. R. Spectral properties of quasiparticle excitations induced by magnetic moments in superconductors. Phys. Rev. B 55, 12648–12661 (1997).

    ADS  CAS  Article  Google Scholar 

  9. 9

    Pan, S. H. et al. Imaging the effects of individual zinc impurity atoms on superconductivity in Bi2Sr2CaCu2O8+δ. Nature 403, 746–750 (2000).

    ADS  CAS  Article  Google Scholar 

  10. 10

    Mendels, P. et al. Macroscopic magnetic properties of Ni and Zn substituted YBa2Cu3Ox. Physica C 235/240, 1595–1596 (1994).

    ADS  Article  Google Scholar 

  11. 11

    Salkola, M. I., Balatsky, A. V. & Scalapino, D. J. Theory of scanning tunneling microscopy probe of impurity states in a d-wave superconductor. Phys. Rev. Lett. 77, 1841–1844 (1996).

    ADS  CAS  Article  Google Scholar 

  12. 12

    Flatté, M. E. & Byers, J. M. Impurity effects on quasiparticle c-axis planar tunneling and STM spectra in high-Tc cuprates. Phys. Rev. Lett. 80, 4546–4549 (1998).

    ADS  Article  Google Scholar 

  13. 13

    Tsuchiura, H., Tanaka, Y., Ogata, M. & Kashiwaya, S. Local density of states around a magnetic impurity in high-TC superconductors based on the t-J model. Phys. Rev. Lett. 84, 3165–3168 (2000).

    ADS  CAS  Article  Google Scholar 

  14. 14

    Flatté, M. E. Quasiparticle resonant states as a probe of short-range electronic structure and Andreév coherence. Phys. Rev. B 61, R14920–14923 (2000).

    ADS  Article  Google Scholar 

  15. 15

    Haas, S. & Maki, K. Quasiparticle bound states around impurities in d x 2 − y 2 -wave superconductors. Phys. Rev. Lett. 85, 2172–2175 (2000).

    ADS  CAS  Article  Google Scholar 

  16. 16

    Martin, I., Balatsky, A. V. & Zaanen, J. Impurity states and interlayer tunneling in high temperature superconductors. Preprint cond-mat/0012446 at <xxx.lanl.gov> (2000).

  17. 17

    Zhang, G.-M., Hu, H. & Yu, L. Marginal Fermi liquid resonance induced by quantum magnetic impurity in d-wave superconductors. Phys. Rev. Lett. 86, 704–707 (2001).

    ADS  CAS  Article  Google Scholar 

  18. 18

    Yazdani, A., Howald, C. M., Lutz, C. P., Kapitulnik, A. & Eigler, D. M. Impurity-induced bound excitations on the surface of Bi2Sr2CaCu2O8. Phys. Rev. Lett. 83, 176–179 (1999).

    ADS  CAS  Article  Google Scholar 

  19. 19

    Yazdani, A., Jones, B. A., Lutz, C. P., Crommie, M. F. & Eigler, D. M. Probing the local effects of magnetic impurities on superconductivity. Science 275, 1767–1770 (1997).

    CAS  Article  Google Scholar 

  20. 20

    Flatté, M. E. & Byers, J. M. Local electronic structure of a single magnetic impurity in a superconductor. Phys. Rev. Lett. 78, 3761–3764 (1997).

    ADS  Article  Google Scholar 

  21. 21

    Maeda, A., Yabe, T., Takebayashi, S., Hase, M. & Uchinokura, K. Substitution of 3d metals for Cu in Bi2(Sr0.6Ca0.4)3Cu2Oy. Phys. Rev. B 41, 4112–4117 (1990).

    ADS  CAS  Article  Google Scholar 

  22. 22

    Kuo, Y. K. et al. Effect of magnetic and nonmagnetic impurities (Ni,Zn) substitution for Cu in Bi2(SrCa)2+n(Cu1-xMx)1+nOy whiskers. Phys. Rev. B 56, 6201–6206 (1997).

    ADS  CAS  Article  Google Scholar 

  23. 23

    Bonn, D. A. et al. Comparison of the influence of Ni and Zn impurities on the electromagnetic properties of YBa2Cu3O6.95. Phys. Rev. B 50, 4051–4063 (1994).

    ADS  CAS  Article  Google Scholar 

  24. 24

    Ishida, K. et al. Cu NMR and NQR studies of impurities-doped YBa2(Cu1-xMx)3O7 (M=Zn and Ni). J. Phys. Soc. Jpn 62, 2803–2818 (1993).

    ADS  CAS  Article  Google Scholar 

  25. 25

    Tokunaga, Y., Ishida, K., Kitaoka, Y. & Asayama, K. Novel relation between spin-fluctuation and superconductivity in Ni substituted high-TC cuprate YBa2Cu3O7: Cu NQR study. Solid State Comm. 103, 43–47 (1997).

    ADS  CAS  Article  Google Scholar 

  26. 26

    Mahajan, A. V., Alloul, H., Collin, G. & Marucco, J. F. 89Y NMR probe of Zn induced local moments in YBa2(Cu1-yZny)3O6+x. Phys. Rev. Lett. 72, 3100–3103 (1994).

    ADS  CAS  Article  Google Scholar 

  27. 27

    Bobroff, J. et al. Spinless impurities in high-TC cuprates: Kondo-like behavior. Phys. Rev. Lett. 83, 4381–4384 (1999).

    ADS  CAS  Article  Google Scholar 

  28. 28

    Bobroff, J. et al. Persistence of Li induced Kondo moments in the superconducting state of cuprates. Phys. Rev. Lett. 86, 4116–4119 (2001).

    ADS  CAS  Article  Google Scholar 

  29. 29

    Williams, G. V. M., Tallon, J. L. & Dupree, R. NMR study of magnetic and non-magnetic impurities in YBa2Cu4O8. Phys. Rev. B 61, 4319–4325 (2000).

    ADS  CAS  Article  Google Scholar 

  30. 30

    Julien, M.-H. et al. 63Cu NMR evidence for enhanced antiferromagnetic correlations around Zn impurities in YBa2Cu3O6.7. Phys. Rev. Lett. 84, 3422–3425 (2000).

    ADS  CAS  Article  Google Scholar 

  31. 31

    Sidis, Y. et al. Quantum impurities and the neutron resonance peak in YBa2Cu3O7: Ni versus Zn. Phys. Rev. Lett. 84, 5900–5903 (2000).

    ADS  CAS  Article  Google Scholar 

  32. 32

    Bernhard, C. et al. Suppression of the superconducting condensate in the high-TC cuprates by Zn substitution and overdoping: Evidence for an unconventional pairing state. Phys. Rev. Lett. 77, 2304–2307 (1996).

    ADS  CAS  Article  Google Scholar 

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Acknowledgements

We acknowledge H. Alloul, P. W. Anderson, A. V. Balatsky, D. Bonn, M. Flatté, M. Franz, D.-H. Lee, K. Maki, I. Martin, P. Monthoux, A. Mourachkine, D. Pines, D. Rokhsar, S. Sachdev, D. J. Scalapino and A. Yazdani for conversations and communications, and J. E. Hoffman for help with data analysis. Support was from the Office of Naval Research, the Department of Energy through an LDRD from LBNL, the UCDRD Program, Grant-in-Aid for Scientific Research on Priority Area (Japan), a COE Grant from the Ministry of Education, Japan, the Miller Inst. for Basic Research (J.C.D.), and by the IBM Graduate Fellowship Program (K.M.L.).

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Correspondence to J. C. Davis.

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Hudson, E., Lang, K., Madhavan, V. et al. Interplay of magnetism and high-Tc superconductivity at individual Ni impurity atoms in Bi2Sr2CaCu2O8+δ. Nature 411, 920–924 (2001). https://doi.org/10.1038/35082019

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