Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-27T02:20:41.564Z Has data issue: false hasContentIssue false
  • English
  • Français

Two Fluid superconductors

Published online by Cambridge University Press:  28 February 2011

Y. Bar-Yam
Y. Bar-Yam*
Affiliation:
Materials Research Department, Weizmann Institute of Science, Rehovot, 76100 Israel
Get access

Abstract

An approach to the theory of high‐Tc superconductivity is discused in which the semiconductor‐like layers between the copper‐oxide planes are more active participants in the superconductivity. Two types of states appear in the theory, a lattice of negative‐U sites and single particle (positive‐U) dispersive states. The negative‐U sites originate in oxygen vacancies and the single particle states in the copper‐oxide planes. The coupling between these two types of states lead to a two‐fluid superconductivity where the negative‐U sites give rise to a charged Bosonic fluid and the single particle states are a Cooper‐paired superconductor. The coupled Fermion‐Boson model for superconductivity is related both to theories of superconductivity in semiconductor‐metal eutectic alloys, and recent suggestions of s‐channel superconductivity of R. Freidberg and T. D. Lee. Basic aspects of general phenomenology are described. The breakdown of Fermi liquid theory in the normal state results from mixing of Fermions and Bosons at the Fermi energy. When the two‐particle states are filled, anti‐ferromagnetism arises from the positive‐U of the single particle states with a contribution from virtual excitation of two‐particle states. Prediction is made of a large class of superconducting materials based on metal‐semiconductor layering.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 169: Symposium M – High Temperature Superconductors: Fundamental Properties and Novel Materials Processing , 1989 , 27
Copyright
Copyright © Materials Research Society 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 Anderson, P. W., Science 235, 1196 (1987)Google Scholar
2 Laughlin, R. B., Science 242, 525 (1988)Google Scholar
3 This is suggested by some calculations: Kasowski, R. V., Hsu, W. Y. and Herman, F., Phys. Rev. B 36, 7248 (1987) The importance of oxygen vacancies, in a different theory, has been discussed by J. C. Phillips see Phys. Rev. Lett. 59, 1856 (1987); Phys. Rev. B 39, 7356 (1989)Google Scholar
4 Bar‐Yam, Y. (preprint)Google Scholar
5 Freidberg, R. and Lee, T. D., Phys. Lett. A 138, 423 (1989); Phys. Rev. B 40, 6745 (1989); D. M. Newns, M. Rasolt, and P. C. Pattnaik, Phys. Rev. B 38, 6513 (1988), D. M. Newns Phys. Rev. B 36, 5595 (1987)Google Scholar
6 Baraff, G. A., Kane, E. O., and Schluter, M., Phys. Rev. B 21, 5662 (1980); G. D. Watkins and J. R. Troxell, Phys. Rev. Lett. 44, 593 (1980); R. Car, P. Kelly, A. Oshiyama, S. T. Pantelides, Phys. Rev. Lett. 52, 1814 (1984); Y. Bar‐Yam and J. D. Joannopoulos, Phys. Rev. Lett. 56, 2203 (1986)Google Scholar
7 Simànek, E., Solid State Comm. 32, 731 (1979); C. S. Ting, D. N. Talwar, and K. L. Ngai Phys. Rev. Lett. 45, 1213 (1980); H.‐B. Schüttler, M. Jarrell and D. J. Scalapino Phys. Rev. Lett. 58, 1147 (1987); Phys. Rev. B 39, 6501 (1989).Google Scholar
8 Nozieres, P. and Schmitt‐ Rink, S., Low Temp, J.. Phys. 59, 195 (1985)Google Scholar
9 Schafroth, R. Phys. Rev. 96, 1442 (1954)Google Scholar
10 Explicit arguments limiting Tc in such systems have not been constructed.Google Scholar
11 see eg. articles this volume.Google Scholar
12 Fiory, A. T., Gurvitch, M., Cava, R. J. and Espinosa, G. P. Phys. Rev. B 36, 7262 (1987)Google Scholar
13 Kim, Y. H., Heeger, A. J., Acedo, L., Sttucky, G. and Wudl, F. Phys. Rev. B 36, 7252 (1987)Google Scholar
14 Rehn, L. E., Baldo, P. M., and Liu, J. Z., this volumeGoogle Scholar