  The interfaces in hybridized structures could give rise to rich phenomena,
which open the way to novel devices with extraordinary performance. Here, we
investigate the interface-related spin transport properties in Fe|Au bilayer
based on first-principle calculation. We find that the spin Hall current in the
Au side near the interface flows in the opposite direction to the bulk spin
Hall current with the magnitude sensitive to the magnetization direction of Fe.
This negative interfacial contribution is attributed to the spin dependent
transmission within a few atomic layers, where a strong interfacial Rashba
spin-orbit coupling exists. Surprisingly, the interfacial spin Hall currents
are found to be not confined at the interface but extend tens of nanometers at
low temperature, which is limited by momentum scattering and therefore much
shorter than the spin diffusion length. In addition, the interfacial swapping
spin currents, as a consequence of the spin precession under the interfacial
Rashba field, are also obtained from our calculation and complete the full spin
transport picture with all non-vanishing components. Our results suggest the
importance of the interface engineering in spin-related transport in
ferromagnetic|non-magnetic heterostructures and the possibility of manipulating
the interfacial transport by the magnetization orientation of the magnetic
layer.
