Quantum transport with spin dephasing: A nonequlibrium Green's function approach

A quantum transport model incorporating spin scattering processes is presented using the nonequilibrium Green's function formalism within the self-consistent Born approximation. This model offers a unified approach by capturing the spin-flip scattering and the quantum effects simultaneously. A numerical implementation of the model is illustrated for magnetic tunnel junction devices with embedded magnetic impurity layers. This model seems to explain three experimentally observed features regarding the dependence of the junction magnetoresistances (JMRs) on the barrier thickness, barrier height, and number of magnetic impurities. It is shown that small variations in magnetic impurity spin states and concentrations could cause large deviations in JMRs.