Spin-polarized currents in a two-terminal quantum ring with spin–orbit interaction

Photoinduced spin current is calculated in a system consisting of a 1D quantum ring with conductors connected to it. It is shown that in the presence of Rashba’s spin–orbit interaction, a current is induced in the ring by circularly polarized radiation. Expressions are derived for the current and electron transmission coefficients taking into account the inelastic interaction with the radiation. It is shown that the spin current is a complex function of the magnetic flux through the ring, radiation frequency, and the spin–orbit coupling constant. In the presence of a potential difference, the interaction with radiation may considerably increase the efficiency of the quantum-ring-based spin filter.