Effect of thermal smearing on the electron-phonon spectral function obtained by inversion of normal metal tunneling data

Abstract

Recently Svistunov et al inverted their normal metal tunneling data to obtain the frequency (Ω) dependence of the electron-phonon spectral function α 2F(Ω) of Pb (driven normal by the application of a magnetic field). Their result is in promising agreement with that obtained using the long established superconducting tunnelling technique, especially if the excess width of the peaks in their spectrum is due to thermal smearing. In this paper the effect of thermal smearing on the inverted α 2F(Ω) of Pb is calculated at 1, 2, and 4 K and a new inversion formula proposed in which the effects of thermal broadening have been eliminated.