Tunable Spin Current Through a Vibrating Molecular Quantum Dot with Spin Bias and Spin Flip Scattering

Abstract

By applying the Lang-Firsov canonical transformation and the Keldysh nonequilibrium Green’s function approach, the effect of the spin-flip scattering on the spin current through a vibrating molecular quantum dot with spin bias is theoretically investigated. We can obtain the spin current from the output terminal, and find that the sign of the spin current can be changed by adjusting the spin-flip strength, and a pure spin current can be generated via the charge bias and the spin bias. In the presence of the electron-phonon interaction, the positions of the current peaks are shifted and the spin current is remarkably suppressed, which leads to the Franck-Condon blockade. Furthermore, it is found that the competition between the EPI and the spin-flip scattering jointly determines the character of the spin current. These results offer us a way to manipulate the spin current in the spin current setup. The proposed device should be realizable with use of the present technology at low temperature.