title: Spin current through quantum-dot spin valves.
abstract: We report a theoretical study of the influence of the Coulomb interaction on the equilibrium spin current in a quantum-dot spin valve, in which the quantum dot described by the Anderson impurity model is coupled to two ferromagnetic leads with noncollinear magnetizations. In the Kondo regime, electrons transmit through the quantum dot via higher-order virtual processes, in which the spin of either lead electrons or a localized electron on the quantum dot may reverse. It is found that the magnitude of the spin current decreases with increasing Coulomb interactions due to spin flip effects on the dot. However, the spatial direction of the spin current remains unchanged; it is determined only by the exchange coupling between two noncollinear magnetizations.
authors.affiliation: Department of Physics, Southeast University, Nanjing 210096, People's Republic of China.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: D Y
authors.initials: DY
authors.lastname: Xing