We know standard spin-orbit coupling and spin Hall effect. But what is the differences in Rashba coupling effect? What changes in Rashba coupling effect?
I am no expert on this, but I will tell you the little that I do know since there are no other answers.
The Rashba effect is very similar to the spin hall effect in the sense that it generates a spin-current. The main difference is that the Rashba effect happens at the interface between two different materials, while the spin hall effect happens in the bulk of a material. So, a multi-layer device can have bulk spin-currents and interface spin-currents. I do not know how the directions of these spin-currents relate to one-another.
Spin-orbit coupling does play a role in the Rashba effect, however the asymmetry of being at the interface does also play a role.