  Spin accumulation and spin current profiles are calculated for a disordered
Pt film subjected to an in-plane electric current within the nonequilibrium
Green function approach. In the bulklike region of the sample, this approach
captures the intrinsic spin Hall effect found in other calculations. Near the
surfaces, the results reveal qualitative differences with the results of the
widely used spin-diffusion model, even when the boundary conditions are
modified to try to account for them. One difference is that the effective
spin-diffusion length for transverse spin transport is significantly different
from its longitudinal counterpart and is instead similar to the mean-free path.
This feature may be generic for spin currents generated via the intrinsic
spin-Hall mechanism because of the differences in transport mechanisms compared
to longitudinal spin transport. Orbital accumulation in the Pt film is only
significant in the immediate vicinity of the surfaces and has a small component
penetrating into the bulk only in the presence of spin-orbit coupling, as a
secondary effect induced by the spin accumulation.
