Magnetotransport through an Aharonov-Bohm ring with parallel double quantum dots coupled to ferromagnetic leads

Using the Keldysh nonequilibrium Green function and equation-of-motion technique,this paper studies the magnetotransport through an Aharonov-Bohm(AB) ring with parallel double quantum dots coupled to ferromagnetic leads.It calculates the transmission probability in both the equilibrium and the nonequilibrium case,analyses the conductance and the tunnel magnetoresistance for various parameters,and obtains some new results.These results show that this system is provided with an excellent spin filtering property,and that a large tunnelling magnetoresistance and a negative tunnelling magnetoresistance can arise by adjusting relative parameters;these facts indicate that this system is a possible candidate for spin valve transistors,and has important applications in spintronics.