Quantum rings as a perfect spin-splitter and spin-filter by using the Rashba effect

Spin related conductance and polarization via an open ballistic quantum nanoring connected to one input lead and two output ones are studied by considering the Rashba effect based on the transfer matrix method. Our probes show that controlling on Rashba strength leads to 100 percent spin polarization while we have high efficiency for the system. In addition, it is possible to design the position of input and output leads in such a way as to optimize the system to work as a spin filtering or spin switching nano device. Also, this apparatus can work as a Stern-Gerlach tool which can be used in some important practical nano-industrial applications. By controlling on Rashba strength in a special design of two output lead positions, it is possible to divide the input charge current into any output ones while the partial output charge current has substantial value in one of two output leads and it is reduced in the other one simultaneously. By controlling on Rashba strength in a special design of output lead positions, the spin conductance can attain a considerable value in one output lead despite an insignificant value in the other one simultaneously.