  It is theoretically predicted that a traveling shear wave will create a spin
current in certain direct-gap (for example III-V compound) semiconductors with
contributions from both the valence bands and the conduction band (for
$n$-doped semiconductors). We show that this spin-current is a property of the
Fermi-Dirac sea, and is controlled by a geometric phase accumulated by the
strain-induced Rashba parameters in a cycle.
