Optically induced spin polarization of an electric current through a quantum dot

We examine a feasibility of the spin polarization of the electron current through a semiconductor quantum dot subject to a continuous circularly polarized optical irradiation resonant to the electron-heavy hole transition. Electrons having a certain spin polarization experience Rabi oscillation and their energy levels are shifted by the Rabi frequency. Correspondingly, the equilibrium chemical potential of the leads and the lead-to-lead bias voltage can be adjusted so only electrons with spin-up polarization or only electrons with spin-down polarization contribute to the current. The temperature dependence of the spin polarization of the current is also discussed.

Figure 1

Zero-temperature conductances for the electrons having different spin projections as a function of the equilibrium chemical potential of the leads for ${\Omega }_R=10\Gamma$.

Figure 2

The total current and the current polarization as functions of the applied lead-to-lead bias.

Figure 3

Temperature dependence of the current polarization.