Rashba Spin-orbit Coupling Effect On The Transmission In The Semiconducting AB Ring

In this paper, using one-dimensional quantum waveguide theory and scattering matrix method, we study the transmission property of a one-dimensional conducting Aharonov-Bohm (AB) ring symmetrically coupled to two ferromagnetic leads and interruped by tunnel barrier in the lower arm. The magnetics moments in the two ferromagnetic electrodes are parallel and antiparallel, respectively. Cosidering the effect of the Rashba spin-orbit coupling and the tunnel barrier, we have calculated the spin-dependent conductance, spin polarization and tunnel magnetoresistance through the scattering matrix method. The conductance amplitude in antiferromagnetic alignment is very different from that in ferromagnetic alignment. The numerical results also show that this structure can provide a large TMR.The contents of this paper includes:1. Using the method of scattering matrix we work out the tranmission conefficient and spin-dependent conductor of the quantum AB ring. It is found that the total magnetic flux and the tunnel barrier can control the two type of the zero conductances and mainly dominate the typical AB resonances of the conductance. The exist of the typical AB resonances in the AB quantum ring point out the A-B phase.2. When the magnetic moments in the ferromagnetic electrods are parallel, the transmission coefficient for spin-up and spin-down electron is different. When the magnetic moments are antiparallel, the spin affect on the electron is vanished, and the conductance decrease obviously. Due to the exchange splitting energy in magnetic leads, the electron obtained visible polarization and larger TMR.3. We calculated the tranmission of electron with the Rashba spin-orbit coupling, the results shown that the tranmission of electron increase and apper the spin-filter phenomenon. The spin-filter dependents on the exist of electric field and magnetic field.