Vibration-mediated Kondo effect in a single-molecule quantum dot coupled to ferromagnetic electrodes

The nonequilibrium Green's function approach and canonical transformation technique are applied to spin-polarized electron transport through a single-molecule quantum dot connected to two ferromagnetic leads in the Kondo regime. A joint effect of electron–electron interactions with finite U and electron–phonon interaction (EPI) leads to a zero-bias anomaly of tunneling magnetoresistance (TMR), the phonon-enhanced negative zero-bias TMR being closer to its experimental value. An effective exchange field on the dot in parallel alignment of magnetizations results in an EPI-dependent splitting of the Kondo peak and EPI-dependent shifts of Kondo satellites. The strong Franck–Condon blockade due to molecule vibrations is also discussed.