Pure spin polarized transport based on Rashba spin orbit interaction through the Aharonov--Bohm interferometer embodied four-quantum-dot ring.

The spin-polarized linear conductance spectrum and current--voltage characteristics in a four-quantum-dot ring embodied into Aharonov--Bohm (AB) interferometer are investigated theoretically by considering a local Rashba spin--orbit interaction. It shows that the spin-polarized linear conductance and the corresponding spin polarization are each a function of magnetic flux phase at zero bias voltage with a period of 2p, and that Hubbard U cannot influence the electron transport properties in this case. When adjusting appropriately the structural parameter of inter-dot coupling and dot-lead coupling strength, the electronic spin polarization can reach a maximum value. Furthermore, by adjusting the bias voltages applied to the leads, the spin-up and spin-down currents move in opposite directions and pure spin current exists in the configuration space in appropriate situations. Based on the numerical results, such a model can be applied to the design of a spin filter device. [ABSTRACT FROM AUTHOR]