Doubled full shot noise in quantum coherent superconductor-semiconductor junctions

Phys Rev Lett. 2003 Feb 14;90(6):067002. doi: 10.1103/PhysRevLett.90.067002. Epub 2003 Feb 10.

Abstract

We performed low temperature shot noise measurements in superconductor (TiN) strongly disordered normal metal (heavily doped Si) weakly transparent junctions. We show that the conductance has a maximum due to coherent multiple Andreev reflections at low energy and that the shot noise is then twice the Poisson noise (S = 4eI). When the subgap conductance reaches its minimum at finite voltage the shot noise changes to the normal value (S = 2eI) due to a large quasiparticle contribution.