  Based on a proper definition of the spin current, we investigate the
spin-Hall effect of heavy holes in narrow quantum wells in the presence of
Rashba spin-orbit coupling by using a spin-density matrix approach. In contrast
to previous results obtained on the basis of the conventional definition of the
spin current, we arrive at the conclusion that an electric-field-induced
steady-state spin-Hall current does not exist in both, pure and disordered
infinite samples. Only an ac field can induce a spin-Hall effect in such
systems.
