Kondo effect and spin-polarized transport through a quantum dot with Rashba spin-orbit interaction

Abstract

By using the finite-$U$ slave-boson approach, we study theoretically the spin accumulation, spin-dependent transport, and the shot noise in a magnetic semiconductor quantum dot induced by the Rashba spin-orbit interactions (SOI) in the Kondo regime. It is shown that the Rashba SOI causes the splitting of the Kondo peak and more conductance dips appear in the Fano-type conductance. The spin-polarized conductance indicates two peaks locating both sides of ${ϵ}_{d}=\ensuremath{-}U∕2$ (${ϵ}_{d}$ and $U$ represent the dot level and the Coulomb repulsion, respectively). In the large bias limit and ignoring the effect of Rashba SOI, the Fano factor can be tuned by the direct coupling between two leads while not related to the Coulomb repulsion. It is found that the Rashba SOI can increase or decrease the Fano factor, which depends on the dot level and the chemical potentials in both leads. When the dot level is below the chemical potentials, the Fano factor increases in the presence of Rashba SOI; otherwise, the Rashba SOI suppresses the Fano factor.