Spin-polarized transport through a coupled double-dot

We propose, theoretically, a new type of design that generates the spin-polarized current through a mesoscopic device composed of lateral double-quantum-dot in the company of time oscillating and spin-polarization dependent tunneling. A formula for the spin-dependent current is obtained and is applied to discuss the transport properties. We demonstrate that the spin and charge currents are controllable by adjusting the gate voltage, the frequency of driving field and the magnitude of the magnetic field as well. In particular an interesting resonance phenomenon of the spin current is qualitatively explained in terms of the exact solutions of a time-dependent Schrödinger equation for an electron moving between the two quantum dots.