Spin-orbit coupling effect by minority interface resonance states in single-crystal magnetic tunnel junctions

Symmetry dependent scattering effect by minority interface resonance states (IRS) has been evidenced in full-epitaxial Fe/MgO/Fe magnetic tunnel junctions (MTJs). Two types of samples with and without carbon doped bottom Fe/MgO interface were fabricated to represent two different types of IRS in the minority channel in the vicinity of the Fermi level. By analysis of the first- principles calculated local density of states (LDOS) and the temperature dependence of conductance in parallel configuration at low bias, we show that the IRS in the carbon free sample is dominated by the delta5 symmetry. This has a major contribution on the majority deltai to delta5 channel scattering and explains the enhancement of the delta5 conductance in the parallel configuration at low temperature. Furthermore, the spectral composition of the IRS in the carbon doped interface is found to be dominated by the delta1 symmetry, which is responsible for the suppression of delta5 channel in the parallel conductance.