Rashba spin-orbit effect on the zero conductance and the magnetoresistance of a quantum ring

Abstract

Using a mode matched scattering matrix method, we study the effect of Rashba spin-orbit coupling and a tunnel barrier on the zero conductance and the tunnel magnetoresistance (TMR) in a one-dimensional conducting Aharonov–Bohm ring symmetrically coupled to two ferromagnetic leads. It is found that the conductances of spin-up and spin-down electrons show periodic variations as the ring’s length changes. The conductance amplitude in antiferromagnetic alignment is very different from that in ferromagnetic alignment. The lifting of the real zero conductance is changed by the spin-orbit interaction and the tunnel barrier. The numerical results also show that this structure can provide a large TMR. When the ring’s length is increased, the TMR varies its period.