Phonon Spectrum of Superconducting Amorphous Bismuth and Gallium by Electron Tunneling

T. T. Chen; J. T. Chen; J. D. Leslie; H. J. T. Smith

doi:10.1103/PhysRevLett.22.526

Phonon Spectrum of Superconducting Amorphous Bismuth and Gallium by Electron Tunneling

T. T. Chen, J. T. Chen, J. D. Leslie, and H. J. T. Smith

Phys. Rev. Lett. 22, 526 – Published 17 March 1969

Abstract

The phonon spectra for amorphous Bi and Ga are derived by using McMillan's inversion program on our tunneling data. The results indicate an extreme "softening of the phonon spectrum" from what is found for crystalline superconductors. Parameters derived from our phonon spectra are used to test recent theories of the transition temperature of amorphous and strong-coupling superconductors, and also to test the McMillan equation for the maximum possible transition temperature in the limit of extremely strong coupling.

Received 16 December 1968

DOI:https://doi.org/10.1103/PhysRevLett.22.526

Authors & Affiliations

T. T. Chen^*, J. T. Chen^†, J. D. Leslie, and H. J. T. Smith

Department of Physics, University of Waterloo, Waterloo, Ontario, Canada

^*Holder of National Research Council of Canada post-graduate scholarship 1967-1969.
^†Holder of National Research Council of Canada post-graduate scholarship 1966-1968 and of a National Research Council of Canada postdoctoral fellowship 1968-1969. Present address: Department of Physics, University of Pennsylvania, Philadelphia, Pa.