  We report a theoretical investigation on spin-Hall conductance fluctuation of
disordered four terminal devices in the presence of Rashba or/and Dresselhaus
spin-orbital interactions in two dimensions. As a function of disorder, the
spin-Hall conductance $G_{sH}$ shows ballistic, diffusive and insulating
transport regimes. For given spin-orbit interactions, a universal spin-Hall
conductance fluctuation (USCF) is found in the diffusive regime. The value of
the USCF depends on the spin-orbit coupling $t_{so}$, but is independent of
other system parameters. It is also independent of whether Rashba or
Dresselhaus or both spin-orbital interactions are present. When $t_{so}$ is
comparable to the hopping energy $t$, the USCF is a universal number $\sim 0.18
e/4\pi$. The distribution of $G_{sH}$ crosses over from a Gaussian distribution
in the metallic regime to a non-Gaussian distribution in the insulating regime
as the disorder strength is increased.

Mesoscale and Nanoscale Physics