Study of coupling effect on the performance of a spin-current diode: Nonequilibrium Green’s function based model

In this paper, spin-dependent transport through a spin diode composed of a quantum dot coupled to a normal metal and a ferromagnetic lead is studied. The current polarization and the spin accumulation are analyzed using the equations of motion method within the nonequilibrium Green’s function formalism. We present a suitable method for computing Green’s function without carrying out any self-consistent calculation. The influence of coupling strength and magnetic field on the spin current is studied and observed that this device cannot work as a spin diode under certain conditions.

► Spin-dependent transport through a magnetic quantum dot is studied by using Keldysh formalism.
► The effects of magnetic field and coupling strength are analyzed.
► We found that the response of the current polarization depends on the magnetic field.
► It is observed that increasing coupling strength affects performance of a spin diode.