Voltage-dependence of the current-phase relation in Josephson microcontacts

The Ginzburg-Landau theory was used by Aslamazov and Larkin to calculate the I(phi) (current-phase) relation in Josephson microcontacts. The result I=I0sin(phi), where I0 is the critical current, was based on the assumption that the bridge dimensions were much smaller than the coherence length of the superconductor. Although their derivation is not strictly correct for a homogeneous contact, the results were found to be in approximate agreement with experiments on microbridges. A linear model of a microcontact is used where the two boundaries of the contact have the equilibrium order parameter, but with the phase difference phi. (Auth.)