Spin Current Generation as a Nonequilibrium Kondo Effect in a Spin-orbit Mesoscopic Interferometer

We study nonequilibrium generation of spin-dependent transport through a single-level quantum dot embedded in a ring with the Rashba spin-orbit coupling. We consider nonmagnetic systems, involving no magnetic field nor ferromagnetic leads. It is theoretically predicted that large spin-dependent current occurs as a combined effect of the Rashba spin-orbit interaction, the Kondo effect, and nonequilibrium effect, without using magnetic field or material. The phenomenon is viewed as a new nonequilibrium correlation effect that disappears when either interaction or finite bias is absent. We show how the Kondo physics is connected with such emergent spin phenomenon by employing the finite interaction slave-boson approach.