Spin accumulation and spin-dependent Andreev reflection current in a T-shaped double quantum dots

By means of the nonequilibrium Green's function (NGF) approach, the spin accumulation and spin-dependent Andreev reflection current in a T-shaped DQD coupled to ferromagnetic and superconducting leads in the presence of spin-flip effect are theoretically investigated. The spin accumulation of quantum dots appears due to the ferromagnetic lead and the Andreev reflection, it is found that the magnitude and the sign of the spin accumulation can be controlled by changing the system parameters such as the bias voltage, the dot level and the spin-flip strength. If the spin-flip effect is taken into account within the QDs, a spin-polarized Andreev reflection current can be generated. Moreover, the spin-polarized Andreev reflection current can be manipulated by tuning the system parameters.