Spin-Flip Transitions in Tunneling through a Quantum Dot Coupled to Ferromagnetic Electrodes

W. Rudziński Department of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland

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Using nonequilibrium Green function formalism the spin-polarized electronic transport through a quantum dot coupled to ferromagnetic electrodes is studied. Arbitrary Coulomb correlations and spin-flip processes are considered in the dot, for both parallel and antiparallel magnetic configurations of the junction. It is found that spin-flip processes suppress the magnetoresistance between each pair of the threshold bias voltages, thus giving rise to sharp tunnel magnetoresistance maxima at the thresholds. The origin of additional steps in the electric current, splitting of the resonance peaks in the corresponding differential conductance as well as negative differential conductance is also discussed in the context of interplay between tunneling processes and the intradot spin-flip transitions.

DOI: 10.12693/APhysPolA.115.281 PACS numbers: 72.25.Mk, 73.63.Kv, 73.23.Hk