  We propose a spin cell based on photon-assisted tunneling through a
conventional semiconductor barrier. The Dresselhaus spin-orbit interaction is
included to break the spin rotation symmetry. Due to the in-plane electric
field induced asymmetric momentum distribution in one lead, continuous flows of
spin currents are driven through a barrier by a AC field. The net charge
current remains zero. The spin current via photon-assisted tunneling can be
readily adjusted via tuning the AC frequency or the in-plane electric field.
This device may function as an ideal spin cell to supply spin currents in the
spintronics circuit.
