Diffusive Conductors as Andreev Interferometers

Abstract

We theoretically study phase-dependent electrical transport in diffusive normal metal--superconductor structures, taking into account (a) the effect of electron-electron interaction in the normal metal and (b) the previously known ``thermal'' effect caused by the energy dependence of the diffusivity. Both effects cause changes in the resistance as a function of the phase between two superconductors, but effect (a) is already present at zero temperature, in contrast to effect (b). A detailed theoretical and numerical analysis demonstrates that the mechanism (b) can fully explain recent experiments by Petrashov et al. [Phys. Rev. Lett. 74, 5268 (1995)].