Phase dependent current statistics in short-arm Andreev interferometer

Abstract

We calculate analytically the current statistics for a short diffusive wire between the normal reservoir and a short superconductor-normal metal-superconductor (SNS) junction, at arbitrary applied voltages and temperatures. The cumulant-generating function oscillates with the phase difference $\varphi$ across the junction, approaching the normal-state value at $\varphi =\pi$. At T=0 and at the applied voltage much smaller than the proximity gap ${\Delta }_{\varphi }$, the current noise $P_I$ doubles and the third current cumulant $C_3$ is 4 times larger with respect to their values in the normal state; at $eV\gg {\Delta }_{\varphi }$ they acquire large excess components. At the gap edge, $eV={\Delta }_{\varphi }$, the effective transferred charge defined through $d{P}_I/dI$ and $d{P}_I/dV$ approaches $0e$ and $3e$, respectively, which makes doubtful the interpretation of these quantities as physical elementary transferred charge. At $T\ne 0$, $C_3$ shows a non-monotonous voltage dependence with a dip near $eV={\Delta }_{\varphi }$.

13 pages, to be published in Proc. NATO ARW "Quantum Transport in Metallic and Hybrid Nanostructures", StPetersburg, 2003