  The lateral current-induced spin polarization in InGaN/GaN superlattices
(SLs) without an applied magnetic field is reported. The fact that the sign of
the nonequilibrium spin changes as the current reverses and is opposite for the
two edges provides a clear signature for the spin Hall effect. In addition, it
is discovered that the spin Hall effect can be strongly manipulated by the
internal strains. A theoretical work has also been developed to understand the
observed strain induced spin polarization. Our result paves an alternative way
for the generation of spin polarized current.
