Temperature Variation of the dc Josephson Current in Pb-Pb Tunnel Junctions

The temperature variation of the dc Josephson current $J_s\mathrm{}\left(T\right)\mathrm{}$ of Pb-Pb tunnel junctions has been investigated both experimentally and theoretically. The experimental data do not agree with the temperature dependence of the dc Josephson current derived by Ambegaokar and Baratoff for the case of two weak coupling superconductors. However, detailed numerical calculations of the temperature variation of the dc Josephson current for a Pb-Pb tunnel junction, which employ strong coupling superconductivity theory throughout, are in reasonably good agreement with the experimental measurements.