Impact of Kondo correlations and spin-orbit coupling on spin-polarized transport in carbon nanotube quantum dot

Spin polarized transport through a quantum dot coupled to ferromagnetic electrodes with noncollinear magnetizations is discussed in terms of nonequilibrium Green functions formalism in the finite-U slave boson mean field approximation. The difference of orientations of the magnetizations of electrodes opens off diagonal spin-orbital transmission and apart from spin currents of longitudinal polarization also spin-flip currents appear. We also study equilibrium pure spin current at zero bias and discuss its dependence on magnetization orientation, spin-orbit coupling strength and gate voltage. Impact of these factors on tunneling magnetoresistance (TMR) is also undertaken. In general spin-orbit coupling weakens TMR, but it can change its sign.

Automated summary

The study discusses spin polarized transport through a quantum dot coupled to ferromagnetic electrodes with noncollinear magnetizations using nonequilibrium Green functions in the finite-U slave boson mean field approximation. The difference in magnetization orientations of the electrodes opens off diagonal spin-orbital transmission and leads to spin-flip currents. The study also explores the impact of spin-orbit coupling, magnetization orientation, and gate voltage on tunneling magnetoresistance (TMR).