FIG. Spin species separation by inhomogeneous magnetic field in a rectangular 30x45-mm region. An electric current flows in 2D film through a region of localized magnetic field, created by a magnet of diameter 10 mm. The spin polarization is measured in the units of the total density. The strength of the electric field, E, is in V/cm. Notice the region of negative ‘‘minority’’ spin polarization that first forms were the current impinges on the region of the magnetic field. For large enough drift velocities, the ‘‘majority’’ and the ‘‘minority’’ carriers form a three-tail structure that extends over the drift length, L_E , downstream. The parameters are characteristic of 10¹⁶ cm-3 Si-doped GaAs:

P= 3000 cm²/Vs, T₁=100 ns, T=10 K.

PHYSICAL REVIEW B 67, 014421 (2003)