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

We investigate quantum spin transport in a structure of a conducting ring embedded in a 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 polarization orientation can be controlled by the electric field. As a result the modulated polarization orientation is a function of the geometric phase which originates from spin-orbital interaction in the ring. (C) 2004 American Institute of Physics.