Current-voltage characteristics of semiconductor/ferromagnet junctions in the spin-blockade regime

It was recently predicted [Phys. Rev. B 75, 193301 (2007)] that spin blockade may develop at nonmagnetic semiconductor/perfect ferromagnet junctions when the electron flow is directed from the semiconductor into the ferromagnet. Here we consider current-voltage characteristics of such junctions. By taking into account the contact resistance, we demonstrate a current stabilization effect: by increasing the applied voltage, the current density through the junction saturates at a specific value. The transient behavior of the current density is also investigated. We show that an abrupt change in the applied voltage is accompanied by a spike in the current density. It is anticipated that this is a common dynamical behavior of the current density in structures with conductivity depending on the level of spin polarization.