Spin accumulation in coupled quantum dots with ferromagnetic and superconducting electrodes

We theoretically investigate the spin accumulation in two parallel coupled quantum dots (QDs) with ferromagnetic and superconducting electrodes. Due to the ferromagnetic lead, the spin accumulation appears on the resonance of Andreev reflection. The spin accumulation in each of the two QDs can be controlled by the gate voltage. The sign of the spin accumulation is also controllable by tuning the bias. Furthermore, tuning the magnetic flux can exchange the amplitude of the spin accumulation in the two QDs. The Aharonov–Bohm oscillation effects also provides a way to control the spin accumulation of each QD.