Phonon-assisted spin current in a hybrid system with a single molecular quantum dot system applied with ac magnetic fields

Abstract

We investigate the spin current through a molecular quantum dot (MQD) ir- radiated with a rotating magnetic field and an oscillating magnetic field by nonequilib- rium Green's function. The rotating magnetic field rotates with the angular frequency ωr around the z-axis with the tilt angle θ, and the time-oscillating magnetic field is lo- cated in the z-axis with the angular frequency ω. Different behaviors have been shown in the presence of electron-phonon interaction(EPI) which plays a significant role in the transport. The spin current displays asymmetric behavior as the source-drain bias eV=0, novel side peaks or shoulders can be found due to the phonon absorption and emission procedure, and the negative spin current becomes stronger as the parameter g increases. However, the spin currents display the same magnitude and the same oscillation behavior in the region m 0B1>3D regardless the parameter g.