Spin-polarized transport through a quantum dot:  Anderson model with on-site Coulomb repulsion

We report on a theoretical analysis of transport characteristics of a spin-valve system formed by a quantum dot connecting to two ferromagnetic electrodes whose magnetic moments are oriented at an angle $\theta$ with respect to each other. We pay special attention to the effects of a finite on-site Coulomb repulsion U. Using the Keldysh nonequilibrium Green’s functions we derived a formula for the current in general terms of bias, temperature, and the parameters $\theta ,U.\mathrm{}$ We have studied the local density of states and nonlinear conductance of this device in the Kondo regime at different polarization angle $\theta .$ Our results suggest that the Kondo peaks in the local density of states and in the conductance can be modulated by $\theta .$