Spin-polarized Andreev reflection and spin accumulation in a quantum-dot Aharonov-Bohm interferometer with spin-orbit interaction effects

We theoretically investigate the spin-orbit interaction effects on the Andreev reflection and the spin accumulation in a quantum dot embedded in an Aharonov-Bohm interferometer. Due to the spin-dependent phase caused by the spin-orbit (SO) interaction, the electron occupation number becomes spin dependent and the spin accumulation can appear in the quantum dot (QD). Furthermore, in the presence of a magnetic flux, the spin accumulation of the dot can even be reversed by tuning the gate voltage. The magnitude and direction of the spin accumulation in the QD can be easily controlled by the gate voltage, magnetic flux, and the SO interaction. The Andreev reflection current also exhibits a spin polarization under the influence of both the spin-orbit interaction and the magnetic field through the ring. The spin polarization of the current can be tuned by varying the spin-orbit interaction strength and the magnetic flux. This provides an efficient mechanism to control the spin accumulation and the Andreev reflection in the quantum dot. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3611398]