Pumping Spin and Charge Currents from Applying a Time-Variant Field and a Magnetic Field to a Quantum Dot

Abstract

Photon-electron pumping effects on a quantum dot connected to two magnetic leads in the presence of both via-dot and over-dot tunneling channels have been investigated by the evolution operator approach. It is found that a time-variant field applied to the quantum dot may give rise to charge and spin pumping at zero bias voltage for asymmetric magnetic junctions. When the magnetic field switch on，the spin-up and spin-down current can be considerably separated，then the highly spin polarized current is also generated.