Abstract
Thermal Difference Reflectance (TDR) Spectroscopy has been used to determinethe superconducting gap parameter for several of the superconducting cupratesover a wide range of energies, ω extending from the infrared (0.3 eV)to the ultraviolet (5.3 eV). A contribution to the pairing is found in eachcase from the phonons, and from an electronic excitation with energy thatranges from 1.6 eV and 2.3 eV for the different compounds attributed to thed 9−d 10 L charge-transfer excitation between Cu and O. In every case thereflectance ratio between the superconducting and normal state, Rs/Rnplotted as a function of photon energy can be well described using theEliashberg theory. The theory also predicted a characteristic shape for thelow energy part of such spectra due to the phonons. We report theobservation of this feature in measurements on films of Tl2Ba2CaCu2O8. Wediscuss the significance of the success of the Eliashberg theory inexplaining these results and successfully predicting new effects in thelight of the correlations that had been thought to invalidate such atheoretical approach.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
REFERENCES
M. J. Holcomb, J. P. Collman, and W. A. Little, Rev. Sci. Instrum. 64, 1867 (1993).
M. J. Holcomb, J. P. Collman, and W. A. Little, Phys. Rev. Lett. 73, 2360 (1994).
M. J. Holcomb, C. L. Perry, J. P. Collman, and W. A. Little, Phys. Rev. B 53, 6734 (1996).
G. M. Eliashberg, Sov. Phys. JETP 11, 696 (1960).
K. Collins, PhD thesis, Physics Department, Stanford University (1997) unpublished.
E. Ratner, PhD thesis, Physics Department, Stanford University (1996), unpublished.
J. Bardeen, L. N. Cooper, and J. R. Schrieffer, Phys. Rev. 108, 1175 (1957).
W. L. McMillan and J. M. Rowell, in R. D. Parks, ed., Superconductivity, Vol. 1 (Dekker, New York, 1969), p. 561.
S. B. Nam, Phys. Rev. 156, 470 (1967).
W. Shaw and J. C. Swihart, Phys. Rev. Lett. 20, 1000 (1968).
M. Tinkham, Introduction to Superconductivity (Krieger, New York, 1980), p. 57.
R. E. Glover and M. Tinkham, Phys. Rev. 108, 243 (1957).
S. B. Nam, Phys. Rev. 156, 487 (1967).
L. H. Palmer and M. Tinkham, Phys. Rev. 165, 688 (1968).
M. J. Holcomb, J. P. Collman, and W. A. Little, Rev. Sci. Instrum. 64, 1867 (1993).
I. Bozovic et al., Phys. Rev. B 42, 1969 (1990).
D. J. Scalapino, in R. D. Parks, ed., Superconductivity, Vol. 1 (Dekker, New York, 1969), pp. 512–514.
C. L. Perry, PhD thesis, Department of Chemistry, Stanford University, Stanford (1996), unpublished.
H. Gutfreund and W. A. Little, Prospects of excitonic superconductivity, in J. T. Devreese, R. P. Evrard, and V. E. Doren, eds., Highly Conducting One Dimensional Solids (Plenum, New York, 1979).
A. B. Migdal, Soviet Phys. JETP 7, 996 (1958).
P. B. Allen and B. Mitrovic, in H. Ehrenreich, F. Seitz, and D. Turnbull, eds., Solid State Physics, Vol. 37 (Academic Press, New York, 1963).
R. Balian and N. R. Werthamer, Phys. Rev. 131, 1553 (1963).
V. J. Emery, Phys. Rev. Lett. 58, 2794 (1987).
L. F. Mattheiss and D. Hamman, Solid State Commun. 63, 395 (1987).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Little, W.A., Collins, K. & Holcomb, M.J. Electronic and Phonon Contributions to the Pairing in the Cuprates. Journal of Superconductivity 12, 89–94 (1999). https://doi.org/10.1023/A:1007733922570
Issue Date:
DOI: https://doi.org/10.1023/A:1007733922570