Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Fully gapped superconductivity in a nanometre-size YBa2Cu3O7–δ island enhanced by a magnetic field

Nature Nanotechnology volume 8, pages 25–30 (2013)Cite this article

Subjects

Abstract

The symmetry of Cooper pairs is central to constructing a superconducting state. The demonstration of a -wave order parameter with nodes represented a breakthrough for high critical temperature superconductors (HTSs)1,2. However, despite this fundamental discovery, the origin of superconductivity remains elusive, raising the question of whether something is missing from the global picture. Deviations from -wave symmetry3,4, such as an imaginary admixture  + is (or idxy), predict a ground state with unconventional properties exhibiting a full superconducting gap and time reversal symmetry breaking5. The existence of such a state, until now highly controversial6,7,8,9,10, can be proved by highly sensitive measurements of the excitation spectrum. Here, we present a spectroscopic technique based on an HTS nanoscale device that allows an unprecedented energy resolution thanks to Coulomb blockade effects, a regime practically inaccessible in these materials previously. We find that the energy required to add an extra electron depends on the parity (odd/even) of the excess electrons on the island and increases with magnetic field. This is inconsistent with a pure -wave symmetry and demonstrates a complex order parameter component that needs to be incorporated into any theoretical model of HTS.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it

$39.95

Learn more

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Energy plots versus gate charge for a normal and superconducting SET.
Figure 2: SET layout.
Figure 3: SET transfer functions at various B.
Figure 4: Experimental stability diagram.

References

  1. Tsuei, C. C. et al. Pairing symmetry and flux quantization in a tricrystal superconducting ring of YBa2Cu3O7–δ . Phys. Rev. Lett. 73, 593–596 (1994).

    Article  CAS  Google Scholar 

  2. Wollman, D. A., van Harlingen, D. J., Lee, W. C., Ginsberg, D. M. & Leggett, A. J. Experimental determination of the superconducting pairing state in YBCO from the phase coherence of YBCO–Pb dc SQUIDs. Phys. Rev. Lett. 71, 2134–2137 (1993).

    Article  CAS  Google Scholar 

  3. Laughlin, R. B. Magnetic induction of + id xy order in high-Tc superconductors. Phys. Rev. Lett. 80, 5188–5191 (1998).

    Google Scholar 

  4. Fogelström, M., Rainer, D. & Sauls, A. Tunneling into current-carrying surface states of high-Tc superconductors. Phys. Rev. Lett. 79, 281–284 (1997).

    Article  Google Scholar 

  5. Volovik, G. E. On edge states in superconductors with time inversion symmetry breaking. JETP Lett. 66, 522–527 (1997).

    Article  Google Scholar 

  6. Kirtley, J. R. et al. Angle-resolved phase-sensitive determination of the in-plane gap symmetry in YBa2Cu3O7−δ . Nature Phys. 2, 190–194 (2006).

    Article  CAS  Google Scholar 

  7. Krishana, K., Ong, N. P., Li, Q., Gu, G. D. & Koshizuka, N. Plateaus observed in the field profile of thermal conductivity in the superconductor Bi2Sr2CaCu2O8 . Science 277, 83–85 (1997).

    Article  CAS  Google Scholar 

  8. Elhalel, G., Beck, R., Leibovitch, G. & Deutscher, G. Transition from a mixed to a pure d-wave symmetry in superconducting optimally doped YBa2Cu3O7–x thin films under applied fields. Phys. Rev. Lett. 98, 137002 (2007).

    Article  CAS  Google Scholar 

  9. Covington, M. et al. Observation of surface-induced broken time-reversal symmetry in YBa2Cu3O7 tunnel junctions. Phys. Rev. Lett. 79, 277–280 (1997).

    Article  CAS  Google Scholar 

  10. Saadaoui, H. et al. Search for broken time-reversal symmetry near the surface of superconducting YBa2Cu3O7–δ films using β-detected nuclear magnetic resonance. Phys. Rev. B 83, 054504 (2011).

    Article  Google Scholar 

  11. Lee, J. et al. Interplay of electron–lattice interactions and superconductivity in Bi2Sr2CaCu2O8+δ . Nature 442, 546–550 (2006).

    Article  CAS  Google Scholar 

  12. Dagotto, E. Complexity in strongly correlated electronic systems. Science 309, 257–262 (2005).

    Article  CAS  Google Scholar 

  13. Khasanov, R. et al. Multiple gap symmetries for the order parameter of cuprates superconductors from penetration depth. Phys. Rev. Lett. 99, 237601 (2007).

    Article  CAS  Google Scholar 

  14. Balatsky, A. V. Spontaneous time reversal and parity breaking in a -wave superconductor with magnetic impurities. Phys. Rev. Lett. 80, 1972–1975 (1998).

    Google Scholar 

  15. Leibovitch, G., Beck, R., Dagan, Y., Hacohen, S. & Deutscher, G. Field-induced nodal order parameter in the tunneling spectrum of YBa2Cu3O7−x superconductor. Phys. Rev. B 77, 094522 (2008).

    Article  Google Scholar 

  16. Gonnelli, R. S. et al. Evidence for pseudogap and phase-coherence gap separation by Andreev reflection experiments in Au/La2−xSrxCuO4 point-contact junctions. Eur. Phys. J. B 22, 411–414 (2001).

    Article  CAS  Google Scholar 

  17. Carmi, R., Polturak, E., Koren, G. & Auerbach, A. Spontaneous macroscopic magnetization at the superconducting transition temperature of YBa2Cu3O7–δ . Nature 404, 853–855 (2000).

    Article  CAS  Google Scholar 

  18. Tsuei, C. C. & Kirtley, J. R. Pairing symmetry in cuprate superconductors. Rev. Mod. Phys. 72, 969–1016 (2000).

    Article  CAS  Google Scholar 

  19. Movshovich, R. et al. Low-temperature anomaly in thermal conductivity of Bi2Sr2Ca(Cu1–xNix)2O8: second superconducting phase? Phys. Rev. Lett. 80, 1968–1971 (1998).

    Article  CAS  Google Scholar 

  20. Schneider, C. W. et al. Pairing symmetry in Bi2Sr2CaCu2O8+x . Eur. Phys. Lett. 64, 489–495 (2003).

    Article  CAS  Google Scholar 

  21. Mößle, M. & Kleiner, R. c-Axis Josephson tunneling between Bi2Sr2CaCu2O8+x and Pb. Phys. Rev. B 59, 4486–4496 (1999).

    Article  Google Scholar 

  22. Hussey, N. E. Low-energy quasiparticles in high-Tc cuprates. Adv. Phys. 51, 1685–1771 (2002).

    Article  CAS  Google Scholar 

  23. Tuominen, M. T., Hergenrother, J. M., Tighe, T. S. & Tinkham, M. Experimental evidence for parity-based 2e periodicity in a superconducting single-electron tunneling transistor. Phys. Rev. Lett. 69, 1997–2000 (1992).

    Article  CAS  Google Scholar 

  24. Averin, D. V. et al. & Likharev, K. K. in Mesoscopic Phenomena in Solids (eds Altshuler, B. et al.) 173–271 (Elsevier, 1991).

    Google Scholar 

  25. Tuominen, M. T., Hergenrother, J. M., Tighe, T. S. & Tinkham, M. Even–odd electron number effects in a small superconducting island: magnetic-field dependence. Phys. Rev. B 47, 11599–11602 (1993).

    Article  CAS  Google Scholar 

  26. Lombardi, F. et al. Intrinsic d-wave effects in YBa2Cu3O7–δ grain boundary Josephson junctions. Phys. Rev. Lett. 89, 207001 (2002).

    Article  CAS  Google Scholar 

  27. Gustafsson, D., Lombardi, F. & Bauch, T. Noise properties of nanoscale YBa2Cu3O7–δ Josephson junctions. Phys. Rev. B 84, 184526 (2011).

    Article  Google Scholar 

  28. Stornaiuolo, D. et al. High quality factor HTS Josephson junctions on low loss substrates. Supercond. Sci. Technol. 24, 045008 (2011).

    Article  Google Scholar 

  29. Johansson, J., Cedergren, K., Bauch, T. & Lombardi, F. Properties of inductance and magnetic penetration depth in (103)-oriented YBa2Cu3O7–δ thin films. Phys. Rev. B 79, 214513 (2009).

    Article  Google Scholar 

  30. Kubatkin, S. E. et al. Coulomb blockade electrometer with a high-Tc island. JETP Lett. 63, 126–132 (1996).

    Article  Google Scholar 

  31. Fitzgerald, R. J., Pohlen, S. L. & Tinkham, M. Observation of Andreev reflection in all-superconducting single-electron transistors. Phys. Rev. B 57, 11073–11076 (1998).

    Article  Google Scholar 

  32. Nakamura, Y., Korotkov, A. N., Chen, C. D. & Tsai, J. S. Singularity-matching peaks in a superconducting single-electron transistor. Phys. Rev. B 56, 5116–5119 (1997).

    Article  CAS  Google Scholar 

  33. Peltonen, J. T., Muhonen, J. T., Meschke, M., Kopnin, N. B. & Pekola, J. P. Magnetic-field-induced stabilization of nonequilibrium superconductivity in a normal-metal/insulator/superconductor junction. Phys. Rev. B 84, 220502 (2011).

    Article  Google Scholar 

  34. Kouwenhoven, L. & Marcus, C. Quantum dots. Phys. World 35–39 June, (1998).

  35. Stejic, G. et al. Effect of geometry on the critical currents of thin films. Phys. Rev. B 49, 1274–1288 (1994).

    Article  CAS  Google Scholar 

  36. Deutscher, G. Andreev–Saint-James reflections: a probe of cuprate superconductors Rev. Mod. Phys. 77, 109–135 (2005).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by the Swedish Research Council (VR) via the Linnaeus Center on Engineered Quantum Systems and the Project ‘Low energy spectrum of HTS explored by quantum effects in nanoscale devices’, as well as the Knut and Alice Wallenberg Foundation. The authors thank F. Tafuri for fruitful discussions. F. Lombardi is also indebted to A. Tzalenchuk for bringing to her attention his pioneering paper on YBCO SET and for valuable comments regarding the manuscript.

Author information

Authors and Affiliations

  1. Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-412 96, Sweden

    D. Gustafsson, M. Fogelström, T. Claeson, S. Kubatkin, T. Bauch & F. Lombardi

  2. Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany

    D. Golubev

Authors
  1. D. Gustafsson
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. D. Golubev
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. M. Fogelström
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. T. Claeson
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. S. Kubatkin
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. T. Bauch
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. F. Lombardi
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

F.L. and S.K. conceived the idea and F.L. designed the experiment. D.G. fabricated the samples and, together with T.B., performed the measurements. D.Go. developed the code for fitting the data. D.G., T.B., D.Go. and F.L. analysed and interpreted the data. M.F., S.K. and T.C. contributed theoretical insights and discussions. F.L. wrote the manuscript in collaboration with all authors.

Corresponding author

Correspondence to F. Lombardi.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 2034 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Gustafsson, D., Golubev, D., Fogelström, M. et al. Fully gapped superconductivity in a nanometre-size YBa2Cu3O7–δ island enhanced by a magnetic field. Nature Nanotech 8, 25–30 (2013). https://doi.org/10.1038/nnano.2012.214

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nnano.2012.214

This article is cited by

Search

Advanced search

Quick links

Find nanotechnology articles, nanomaterial data and patents all in one place. Visit Nano by Nature Research