Manipulation of Andreev reflections in the single-dot quantum ring with one side-coupled superconductor

We investigate the Andreev reflections in a single-dot quantum ring with one s-wave superconductor side-coupled to the quantum dot, by considering the presence of local Rashba interaction and magnetic flux. It shows that in this system, the local Rashba interaction induces apparent spin polarizations of the local Andreev reflections, with their directions depending on the Rashba interaction and the lead index, respectively. Nevertheless, the crossed Andreev reflection cannot be polarized, and its magnitude can be adjusted by the threaded local magnetic flux. We propose this structure to be the promising candidate for achieving the manipulation of Andreev reflections. (paper)