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Imaging the granular structure of high-Tc superconductivity in underdoped Bi2Sr2CaCu2O8+δ

Abstract

Granular superconductivity occurs when microscopic superconducting grains are separated by non-superconducting regions; Josephson tunnelling between the grains establishes the macroscopic superconducting state1. Although crystals of the copper oxide high-transition-temperature (high-Tc) superconductors are not granular in a structural sense, theory suggests that at low levels of hole doping the holes can become concentrated at certain locations resulting in hole-rich superconducting domains2,3,4,5. Granular superconductivity arising from tunnelling between such domains would represent a new view of the underdoped copper oxide superconductors. Here we report scanning tunnelling microscope studies of underdoped Bi2Sr2CaCu2O8+δ that reveal an apparent segregation of the electronic structure into superconducting domains that are 3 nm in size (and local energy gap <50 meV), located in an electronically distinct background. We used scattering resonances at Ni impurity atoms6 as ‘markers’ for local superconductivity7,8,9; no Ni resonances were detected in any region where the local energy gap Δ > 50 ± 2.5 meV. These observations suggest that underdoped Bi2Sr2CaCu2O8+δ is a mixture of two different short-range electronic orders with the long-range characteristics of a granular superconductor.

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Figure 1: Typical gap maps from underdoped and as-grown Bi-2212 samples, each showing an area of 560 Å × 560 Å.
Figure 2: Data obtained at high spatial resolution, showing the typical spatial interrelationship of Δ and G(Δ) for underdoped Bi-2212.
Figure 3: Typical series of dI/dV spectra illustrating how the two distinct types of regions are apparent in the raw data.
Figure 4: Analysis of the relationship between Ni scattering resonances and local Δ.

References

  1. Simánek, E. Inhomogeneous Superconductors: Granular and Quantum Effects (Oxford Univ. Press, New York, 1994).

    Google Scholar 

  2. Gor'kov, L. P. & Sokol, A. V. Phase stratification of an electron liquid in the new superconductors. JETP Lett. 46, 420–423 (1987).

    ADS  Google Scholar 

  3. Zaanen, J. & Gunnarsson, O. Charge magnetic domain lines and the magnetism of high-Tc oxides. Phys. Rev. B 40, 7391–7394 (1989).

    Article  ADS  CAS  Google Scholar 

  4. Emery, V. J., Kivelson, S. A. & Lin, H. Q. Phase separation in the t-J model. Phys. Rev. Lett. 64, 475–478 (1990).

    Article  ADS  CAS  Google Scholar 

  5. Emery, V. J. & Kivelson, S. A. Frustrated electronic phase separation and high-temperature superconductors. Physica C 209, 597–621 (1993).

    Article  ADS  CAS  Google Scholar 

  6. Hudson, E. W. et al. Interplay of magnetism and high-Tc superconductivity at individual Ni impurity atoms in Bi2Sr2CaCu2O8+δ. Nature 411, 920–924 (2001).

    Article  ADS  CAS  Google Scholar 

  7. Flatté, M. E. Nickel probes superconductivity. Nature 411, 901–903 (2001).

    Article  ADS  Google Scholar 

  8. Flatté, M. E. Quasiparticle resonant states as a probe of short-range electronic structure and Andreév coherence. Phys. Rev. B 61, R14920–R14923 (2000).

    Article  ADS  Google Scholar 

  9. Kruis, H. V., Martin, I. & Balatsky, A. V. Impurity-induced resonant state in a pseudogap state of a high-Tc superconductor. Phys. Rev. B 64, 054501-1–054501-4 (2001).

    Article  ADS  Google Scholar 

  10. Liu, J.-X., Wan, J.-C., Goldman, A. M., Chang, Y. C. & Jiang, P. Z. Features of the density of states of high-Tc superconductors probed by vacuum tunneling. Phys. Rev. Lett. 67, 2195–2198 (1991).

    Article  ADS  CAS  Google Scholar 

  11. Chang, A., Rong, Z. Y., Ivanchenko, Y. M., Lu, F. & Wolf, E. L. Observation of large tunneling-conductance variations in direct mapping of the energy gap of single-crystal Bi2Sr2CaCu2O8-x. Phys. Rev. B 46, 5692–5698 (1992).

    Article  ADS  CAS  Google Scholar 

  12. Cren, T. et al. Influence of disorder on the local density of states in high-Tc superconducting thin films. Phys. Rev. Lett. 84, 147–150 (2000).

    Article  ADS  CAS  Google Scholar 

  13. Howald, C., Fournier, P. & Kapitulnik, A. Inherent inhomogeneities in tunneling spectra of Bi2Sr2CaCu2O8-x crystals in the superconducting state. Phys. Rev. B 64, 100504-1–100504-4 (2001).

    Article  ADS  Google Scholar 

  14. Cren, T., Roditchev, D., Sacks, W. & Klein, J. Nanometer scale mapping of the density of states in an inhomogeneous superconductor. Europhys. Lett. 54, 84–90 (2001).

    Article  ADS  CAS  Google Scholar 

  15. Pan, S. H. et al. Microscopic electronic inhomogeneity in the high-Tc superconductor Bi2Sr2CaCu2O8+x. Nature 413, 282–285 (2001).

    Article  ADS  CAS  Google Scholar 

  16. Ovchinnikov, Y. N., Wolf, S. A. & Kresin, V. Z. Intrinsic inhomogeneities in superconductors and the pseudogap phenomenon. Phys. Rev. B 63, 064524-1–064524-6 (2001).

    Article  ADS  Google Scholar 

  17. Ghosal, A., Randeria, M. & Trivedi, N. Inhomogeneous pairing in highly disordered s-wave superconductors. Phys. Rev. B 65, 014501-1–014501-13 (2002).

    ADS  Google Scholar 

  18. Burgy, J., Mayr, M., Martin-Mayor, V., Moreo, A. & Dagotta, E. Colossal effects in transition metal oxides caused by intrinsic inhomogeneities. Phys. Rev. Lett. 87, 277202-1–277202-4 (2001).

    Article  ADS  Google Scholar 

  19. Wang, Z., Engelbrecht, J. R., Wang, S., Ding, H. & Pan, S. H. Inhomogeneous d-wave superconducting state of a doped Mott insulator. Preprint cond-mat/0107004 at 〈http://xxx.lanl.gov〉 (2001); Phys. Rev. B 65, (2002) (in the press).

  20. Martin, I. & Balatsky, A. V. Doping-induced inhomogeneity in high-Tc superconductors. Physica C 357–360, 46–48 (2001).

    Article  ADS  Google Scholar 

  21. Wang, Q.-H., Han, J. H. & Lee, D.-H. Pairing near the Mott insulating limit. Phys. Rev. B 65, 054501-1–054501-4 (2002).

    ADS  Google Scholar 

  22. Phillips, J. C. & Jung, J. Nanodomain structure and function of high-temperature superconductors. Phil. Mag. B 81, 745–756 (2001).

    Article  ADS  CAS  Google Scholar 

  23. Deutscher, G. & Müller, K. A. Origin of superconductive glassy state and extrinsic critical currents in high-Tc oxides. Phys. Rev. Lett. 59, 1745–1747 (1987).

    Article  ADS  CAS  Google Scholar 

  24. Corson, J., Orenstein, J., Oh, S., O'Donnell, J. & Eckstein, J. N. Nodal quasiparticle lifetime in the superconducting state of Bi2Sr2CaCu2O8+δ. Phys. Rev. Lett. 85, 2569–2572 (2000).

    Article  ADS  CAS  Google Scholar 

  25. Barabash, S., Stroud, D. & Hwang, I.-J. Conductivity due to classical phase fluctuations in a model for high-Tc superconductors. Phys. Rev. B 61, R14924–R14927 (2000).

    Article  ADS  CAS  Google Scholar 

  26. Loram, J. W., Luo, J. L., Cooper, J. R., Liang, W. Y. & Tallon, J. L. The condensation energy and pseudogap energy scale of Bi:2212 from the electronic specific heat. Physica C 341–348, 831–834 (2000).

    Article  ADS  Google Scholar 

  27. Takigawa, M. & Mitzi, D. B. NMR studies of spin excitations in superconducting Bi2Sr2CaCu2O8+x single crystals. Phys. Rev. Lett. 73, 1287–1290 (1994).

    Article  ADS  CAS  Google Scholar 

  28. Fong, H. F. et al. Neutron scattering from magnetic excitations in Bi2Sr2CaCu2O8+x. Nature 398, 588–591 (1999).

    Article  ADS  CAS  Google Scholar 

  29. Vobornik, I. et al. Alternative pseudogap scenario: Spectroscopic analogies between underdoped and disordered Bi2Sr2CaCu2O8+x. Phys. Rev. B 61, 11248–11250 (2000).

    Article  ADS  CAS  Google Scholar 

  30. Krasnov, V. M., Kovalev, A. E., Yurgens, A. & Winkler, D. Magnetic field dependence of the superconducting gap and the pseudogap in Bi2212 and HgBr2-Bi2212, studied by intrinsic tunneling spectroscopy. Phys. Rev. Lett. 86, 2657–2660 (2001).

    Article  ADS  CAS  Google Scholar 

  31. Suzuki, M. & Watanabe, T. Discriminating the superconducting gap from the pseudogap in Bi2Sr2CaCu2O8+x by interlayer tunneling spectroscopy. Phys. Rev. Lett. 85, 4787–4790 (2000).

    Article  ADS  CAS  Google Scholar 

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Acknowledgements

We thank A. V. Balatsky, E. Dagotto, M. E. Flatté, S. A. Kivelson, V. Z. Kresin, R. B. Laughlin, J. W. Loram, D.-H. Lee, P. A. Lee, I. Martin, D. K. Morr, S. H. Pan, D. Pines, D. J. Scalapino, Z.-X. Shen, N. Trivedi and S. A. Wolf for discussions and communications. This work was supported by the LDRD program of Lawrence Berkeley National Laboratory, by the ONR, by the CULAR program of Los Alamos National Laboratory, by the Miller Research Foundation (J.C.D.), by IBM (K.M.L.), by Grant-in-Aid for Scientific Research, by a COE grant from the Ministry of Education, and by an International Joint Research Grant from NEDO (Japan).

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Lang, K., Madhavan, V., Hoffman, J. et al. Imaging the granular structure of high-Tc superconductivity in underdoped Bi2Sr2CaCu2O8+δ. Nature 415, 412–416 (2002). https://doi.org/10.1038/415412a

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