  We predict that when an alternating voltage is applied to a semiconducting
system with inhomogeneous electron density in the direction perpendicular to
main current flow, the spin Hall effect results in a transverse voltage
containing a double-frequency component. We also demonstrate that there is a
phase shift between applied and transverse voltage oscillations, related to the
general memristive behavior of semiconductor spintronic systems. A different
method to achieve frequency doubling based on the inverse spin Hall effect is
also discussed.
