LAUSR

We study controlled spin transport through a two-dimensional (2D) spin-orbit coupled quantum ring of finite width. Complete analytical expressions for the energy spectrum and wave function of a 2D ring are obtained in the presence of both an external magnetic field and Rashba spin-orbit interaction. These results have been used to investigate the magnetoconductance of the ring in which an interface electric field leads to the Rashba mechanism. Nonperiodicity of the ground-state angular momentum transition with respect to the external magnetic field is observed for a 2D ring which is in contrast to the perfectly periodic transition spectrum of the one-dimensional (1D) ring. Our analytical model has successfully reproduced the salient features of the magnetoconductance of the ring. In 1D as well as 2D ring geometries, the probability amplitude for the transfer of electron spin, polarized in the direction of an external magnetic field, is found to be maximum irrespective of the polarization of the incoming spin. Since the spin polarization of the transmitted electron changes continuously with Rashba coupling, this system can act as a tunable spin switch electrically controlled by gate voltage.