Proximity Effects between Conventional and Unconventional Superconductors

  • A. J. Millis
  • D. Rainer
  • J. Sauls


In this article I review recent theoretical work on the possibility of using tunneling and proximity effect experiments to study unconventional superconductors. The basic idea is simple: as shown in Fig. 1 one places a thin layer of some well understood conventional superconductor in good metallic contact with the superconductor one wishes to study, and then measures (e.g. by tunneling at the outer edge the conventional layer) how the superconducting properties of the conventional material are altered by its proximity to the unconventional material. To study this question theoretically one has to solve the gap equation for the inhomogeneous system. Because the symmetry and the physical origin of the pairing interaction may be different for conventional than for unconventional superconductors, it is possible that the proximity effect is different between two conventional superconductors than it is between a conventional and an unconventional superconductor. Our understanding of the nature and observability of these differences is still preliminary. A useful theoretical technique for calculating such proximity effects has only recently been proposed, and only a few calculations in simple model systems have been done. The results from this preliminary work are not encouraging: proximity etlects involving unconventional superconductivity seem to differ only in subtle ways from those involving only conventional superconductivity; further, proximity effect experiments do not seem to provide a useful method of distinguishing unconventional singlet (e.g. d-wave) from triplet superconductivity.


Cooper Pair Proximity Effect Superconducting Order Parameter Good Electrical Contact Unconventional Superconductor 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1).
    P. G. deGennes, Rev. Mod. Phys. 36, 225 (1964).CrossRefGoogle Scholar
  2. 2).
    G. Deutscher and P. G. deGennes in Superconductivity ed. R. D. Parks ( Marcel Dekker: New York, 1969 ).Google Scholar
  3. 3).
    P. W. Anderson and W. F. Brinkman in The Physics of Solid and Liquid Helium, ed. K. H. Benneman and J. B. Ketterson ( John Wiley and Sons: New York, 1978 ) p. 177.Google Scholar
  4. 4).
    P. A. Lee, T. M. Rice, J. W. Serene, L. J. Sham and J. W. Wilkins, Comm. Cond. Mat. Phys. 12, 99, (1986).Google Scholar
  5. 5).
    G. E. Volovik and L. P. Gorkov, Sov. Phys. JETP 61 843, (1985).Google Scholar
  6. 6).
    E. I. Blount, Phys. Rev. B 32 2935 (1985).CrossRefGoogle Scholar
  7. 7).
    A. A. Abrikosov, L. P. Gorkov and I. E. Dzyaloshinski, Methods of Quantum Field Theory in Statistical Physics, trans. R. A. Silverman ( Dover: New York, 1963 ).Google Scholar
  8. 8).
    R. Balian and N. R. Werthamer, Phys. Rev. 131 1553 (1963).CrossRefGoogle Scholar
  9. 9).
    A. J. Millis, unpublished.Google Scholar
  10. 10).
    V. Ambegaokar, P. G. deGennes and D. Rainer, Phys. Rev. A 9, 2676 (1974).CrossRefGoogle Scholar
  11. 11).
    L. J. Buchholtz and G. Zwicknagl, Phys. Rev. B23, 5788 (1981).CrossRefGoogle Scholar
  12. 12).
    A. J. Millis, D. Rainer and J. A. Sauls, to be published.Google Scholar
  13. 13).
    J. Sauls, Z. Zou. and P. W. Anderson, unpublished.Google Scholar
  14. 14).
    V. B. Geshkenbein and A. I. Larkin, JETP Lett. 40, p. 395, 1986.Google Scholar
  15. 15).
    A. J. Millis, to be published.Google Scholar
  16. 16).
    A. J. Millis in Proceedings of the International Conference on Materials and Mechanisms of Superconductivity 1985 eds. K. Gschneider and E. L. Wolf, Physica 135B, p. 69 (1985).Google Scholar
  17. 17).
    W. L. McMillan, Phys. Rev. 175 537 (1968).CrossRefGoogle Scholar
  18. 18).
    K. Scharnberg, D. Fay, and N. Schopohl, J. de Physique 39, C6 - 481 (1978).Google Scholar
  19. 19).
    E. W. Fenton, Sol. State. Comm. 54, 705 (1985).CrossRefGoogle Scholar
  20. 20).
    G. Eilenberger, Z. Phys. 214, 195. (1968).CrossRefGoogle Scholar
  21. 21).
    J. W. Serene and D. Rainer, Phys. Rep. 101, 221 (1983).CrossRefGoogle Scholar
  22. 22).
    A. V. Zaitsev, Zh. Exph. Teor Fiz. 59 1015 (1984).Google Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • A. J. Millis
    • 1
  • D. Rainer
    • 2
  • J. Sauls
    • 3
  1. 1.AT&T Bell LaboratoriesMurray HillUSA
  2. 2.Physikalisches InstitutUniversität BayreuthBayreuthWest Germany
  3. 3.Dept. of PhysicsPrinceton UniversityPrincetonUSA

Personalised recommendations