Controllable quantum spin precession by Aharonov-Casher phase in conducting ring

We investigate quantum spin transport in a structure of conducting ring, embedded in textured electric field, with two leads, and obtain an exact solution for the problem. The spin precession induced by the Aharonov-Casher phase is studied. It is shown that the spin-polarized current and its polarizability can be controlled by the electric field. As a result the polarizability is a function of the geometric phase which originates from the spin-orbital interaction in the ring. 72.25.-b, 03.65.Vf