Andreev Reflection in Transport through a Quantum Dot Coupled to Ferromagnetic and Superconducting Electrodes

Spin-dependent tunneling through a quantum dot coupled to one ferromagnetic and one superconducting electrodes is studied theoretically in the Andreev reection regime.Electrical conductance is calculated in terms of the nonequilibrium Green function technique.Eects due to the Zeeman splitting of the dot level are analyzed in both linear and nonlinear transport regimes, and are compared with the corresponding eects due to coherent intradot spin rotation.