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Pairing fluctuations in the pseudogap state of copper-oxide superconductors probed by the Josephson effect

Abstract

The phase diagram of high-temperature superconductors is still to be understood1. In the low-carrier-doping regime, a loss of spectral weight in the electronic excitation spectrum—the so-called pseudogap—is observed above the superconducting temperature Tc, and below a characteristic temperature T* (ref. 2). First observed in the spin channel by NMR measurements, the pseudogap has also been observed in the charge channel by scanning probe microscopy and photoemission experiments, for instance2. An important issue to address is whether this phenomenon is related to superconductivity or to a competing ‘hidden’ order. In the superconductivity case, it has been suggested that superconducting pairing fluctuations may be responsible, but this view remains to be tested experimentally. Here, we have designed a Josephson-like experiment to probe directly the fluctuating pairs in the normal state. We show that fluctuations survive only in a restricted range of temperature above Tc, well below T*, and therefore cannot explain the opening of the pseudogap at higher temperature.

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Figure 1: Trilayer junction.
Figure 2: Tc of the trilayer junction.
Figure 3: Current–voltage characteristics of a 10×10 μm2 junction made with a 50-nm-thick barrier.
Figure 4: Conductance of the junction above TcUD.

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References

  1. Norman, M. R. & Pepin, C. The electronic nature of high temperature cuprate superconductors. Rep. Prog. Phys. 66, 1547–1610 (2003).

    Article  ADS  Google Scholar 

  2. Timusk, T. & Statt, B. The pseudogap in high-temperature superconductors: An experimental survey. Rep. Prog. Phys. 62, 61–122 (1999).

    Article  ADS  Google Scholar 

  3. Ding, H. et al. Spectroscopic evidence for a pseudogap in the normal state of underdoped high-Tc superconductors. Nature 382, 51–54 (1996).

    Article  ADS  Google Scholar 

  4. Norman, M. R. et al. Destruction of the Fermi surface in underdoped high-Tc superconductors. Nature 392, 157–160 (1998).

    Article  ADS  Google Scholar 

  5. Renner, Ch., Revaz, B., Genoud, J.-Y., Kadowaki, K. & Fischer, Ø. Pseudogap precursor of the superconducting gap in under- and overdoped Bi2Sr2CaCu2O8+δ . Phys. Rev. Lett. 80, 149–152 (1998).

    Article  ADS  Google Scholar 

  6. Emery, V. J. & Kivelson, S. A. Importance of phase fluctuations in superconductors with small superfluid density. Nature 374, 434–437 (1995).

    Article  ADS  Google Scholar 

  7. Randeria, M. in Proc, Int. School of Physics ‘Enrico Fermi’ Course CXXXVI on High Temperature Superconductors (eds Iadonisi, G., Schrieffer, J. R. & Chiafalo, M. L.) 53–75 (IOS Press, Amsterdam, 1998).

    Google Scholar 

  8. Ferrell, R. A. Fluctuations and the superconducting phase transition : II. Onset of the Josephson tunneling and paraconductivity of a junction. Low. Temp. Phys 1, 423–442 (1969).

    Article  ADS  Google Scholar 

  9. Scalapino, D. J. Pair tunneling as a probe of fluctuations in superconductors. Phys. Rev. Lett. 24, 1052–1055 (1970).

    Article  ADS  Google Scholar 

  10. Anderson, J. T. & Goldman, A. M. Experimental determination of the pair susceptibility of a superconductor. Phys. Rev. Lett. 25, 743–747 (1970).

    Article  ADS  Google Scholar 

  11. Janko, B., Kosztin, I., Levin, K., Norman, M. R. & Scalapino, D. J. Incoherent pair tunneling as a probe of the cuprate pseudogap. Phys. Rev. Lett. 82, 4304–4307 (1999).

    Article  ADS  Google Scholar 

  12. Barone, A. & Patterno, G. Physics and Applications of the Josephson Effect (Wiley–Intersciences, New York, 1982).

    Book  Google Scholar 

  13. Golubov, A. A. et al. Resonant tunneling in Y(Dy)Ba2Cu3O7−δ/PrBa2Cu3−xGaxO7−δ/Y(Dy)Ba2Cu3O7−δ ramp type Josephson junctions. Physica C 235–240, 3261–3262 (1994).

    Article  ADS  Google Scholar 

  14. Bari, M. A. C-axis tunneling in YBa2Cu3O7−δ trilayer junctions with PrBa2Cu3−xGaxO7−δ barrier. Physica C 256, 227–235 (1996).

    Article  ADS  Google Scholar 

  15. Devyatov, I. A. & Kupriyanov, M. Yu. Resonant tunneling through SIS junctions of arbitrary size. Zh. Eksp. Teor. Fiz. 112, 342–352 (1997); JETP Lett. 85, 189–194 (1997).

  16. Yoshida, J. & Nagano, T. Tunneling and hopping conduction via localised states in thin PrBa2Cu3O7−x barriers. Phys. Rev. B 55, 11860–11871 (1997).

    Article  ADS  Google Scholar 

  17. Glazman, L. I. & Matveev, K. A. Inelastic tunnelling across thin amorphous films. Sov. Phys. JETP 67, 1276–1282 (1988).

    Google Scholar 

  18. Kadin, A. M. & Goldman, A. M. Pair-field susceptibility and superconducting tunneling: A macroscopic approach. Phys. Rev. B 25, 6701–6710 (1982).

    Article  ADS  Google Scholar 

  19. Devyatov, I. A. & Kupriyanov, M. Yu. Current–voltage characteristics of a SIS structures with localised states in the material of the barrier layer. Zh. Eksp. Teor. Fiz. 114, 687–699 (1998); JETP Lett. 87, 375–381 (1998).

  20. Takenaka, K., Mizuhashi, K., Takagi, H. & Uchida, S. Interplane charge transport in YBa2Cu3O7−y: Spin-gap effect on in-plane and out-of-plane resistivity. Phys. Rev. B 50, 6534 (1994).

    Article  ADS  Google Scholar 

  21. Corson, J., Mallozzi, R., Orenstein, J. J. N., Eckstein, J. N. & Bozovic, I. Vanishing of phase coherence in underdoped Bi2Sr2CaCu2O8+δ . Nature 398, 221–223 (1999).

    Article  ADS  Google Scholar 

  22. Xu, Z. A. et al. Vortex-like excitations and the onset of superconducting phase fluctuation in underdoped La2−xSrxCuO4 . Nature 406, 486–488 (2000).

    Article  ADS  Google Scholar 

  23. Wang, Y. et al. Onset of the vortex-like Nernst signal above Tc in La2−xSrxCuO4 and Bi2Sr2−yLayCuO6 . Phys. Rev. B 64, 224519 (2001).

    Article  ADS  Google Scholar 

  24. Rullier-Albenque, F. et al. Nernst effect and disorder in the normal state of high-Tc cuprates. Phys.Rev. Lett. 96, 067002 (2006).

    Article  ADS  Google Scholar 

  25. Ussishkin, I., Sondhi, S. L. & Huse, D. A. Gaussian superconducting fluctuations, thermal transport, and the Nernst effect. Phys. Rev. Lett. 89, 287001 (2002).

    Article  ADS  Google Scholar 

  26. Pourret, A. et al. Observation of the Nernst signal generated by fluctuating Cooper pairs. Nature Phys. 2, 683–686 (2006).

    Article  ADS  Google Scholar 

  27. Carrington, A., Mackenzie, A. P., Lin, C. T. & Cooper, J. R. Temperature dependence of the Hall angle in single-crystal YBa2(Cu1−xCox)3O7−δ . Phys. Rev. Lett. 69, 2855–2858 (1992).

    Article  ADS  Google Scholar 

  28. Bergeal, N. et al. Using ion irradiation to make high-Tc Josephson junctions. J. Appl. Phys. 102, 083903 (2007).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

We acknowledge M. Grilli, S. Caprara, C. Castellani and C. Di Castro for stimulating discussions. We also thank P. Monod, O. Kaitasov and C. Dupuis.

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Correspondence to N. Bergeal or J. Lesueur.

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Bergeal, N., Lesueur, J., Aprili, M. et al. Pairing fluctuations in the pseudogap state of copper-oxide superconductors probed by the Josephson effect. Nature Phys 4, 608–611 (2008). https://doi.org/10.1038/nphys1017

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