Open AccessTunneling measurements of superconducting quasi-particle density of states and calculation of phonon spectra
Author(s) -
J. M. Rowell
Publication year - 1970
Publication title -
journal of research of the national bureau of standards. section a. physics and chemistry
Language(s) - English
Resource type - Journals
eISSN - 2376-5704
pISSN - 0022-4332
DOI - 10.6028/jres.074a.046
Subject(s) - quantum tunnelling , superconductivity , condensed matter physics , density of states , bismuth , scanning tunneling spectroscopy , semiconductor , phonon , materials science , diode , physics , quantum mechanics , metallurgy
It is an unfortunate fact that the tunneling technique, which has proved incredibly successful in the study of superconductivity, has given little information about the normal state properties of metals and semiconductors. It will be shown that, in the determination of the superconducting quasi-particle density of states, it is the change in density induced by the onset of superconductivity which is measured rather than the total density. Returning to the problem of normal materials, a review of the limited achievements and failures of tunneling will be presented. This will include the influence of band edges on tunneling in p-n diodes and metal-semiconductor contacts, the structures observed in tunneling into bismuth and the negative results obtained in nickel and palladium. The dominant effect of the change in barrier shape in most of these tunneling characteristics will be illustrated.