Analytical calculation of the excess current in the Octavio–Tinkham–Blonder–Klapwijktheory

Abstract

We present an analytical derivation of the excess current in Josephson junctionswithin the Octavio–Tinkham–Blonder–Klapwijk theory for both symmetric andasymmetric barrier strengths. We confirm the result found numerically by Flensberget al for equal barriers (1988 Phys. Rev. B 38 8707), including the prediction ofnegative excess current for low transparencies, and we generalize it for differingbarriers. Our analytical formulae provide for convenient fitting of experimental data,also in the less studied, but practically relevant, case of the barrier asymmetry.