The QDs is a zero-dimensional device where various interactions exist and is widely investigated in recent years for its tunable size, shape, quantized energy levels, and carrier number. Recently, an Aharnov-Bohm (AB) ring device, in which one or two quantum dots (QDs) having RSOI are located in its arms, is proposed to realize the spin-polarized transport. Many recent experimental and theoretical works indicate that the spin-polarization based on the RSOI can reach as high as 100% or infinite, and then attracted a lot of interest. It can couple the spin degree of freedom to its orbital motion, thus making it possible to control the electron spin in a nonmagnetic way. The RSOI is a relativistic effect at the low-speed limit and is essentially the influence of an external field on a moving spin. But if a device is formed in a semiconductor two-dimensional electron gas system with an asymmetrical-interface electric field, Rashba spin–orbit interaction (RSOI) will occur. The electric field usually does not act on the spin.

Due to its unsatisfactory efficiency in nano-scale structures, generating and controlling a spin-polarized current with all-electrical means in mesoscopic structures has been an actively researched topic in recent years.

The traditional standard method of spin control depends on the spin injection technique, with mainly relies on optical techniques and the usage of a magnetic field or ferromagnetic material. With the rapid progress in miniaturization of the solid-state devices, the effect of carriers’ spin in semiconductor has attracted considerable attention for its potential applications in photoelectric devices and quantum computing.

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