Spin current generation and detection by a double quantum dot structure

We propose a device acting as a spin valve which is based on a double quantum dot structure with parallel topology. Using the exact analytical solution for the noninteracting case we argue that, at a certain constellation of system parameters and externally applied fields, the electric current through the constriction can become almost fully spin-polarized. We discuss the influence of the coupling asymmetry, finite temperatures and interactions on the efficiency of the device and make predictions for the experimental realization of the effect.