electronstaticdifferentpotential

[xiaolight]

I have done the electronstaticdifferncepotential  in ATK which is below. So why does the curve go upward in the FeCl2 region which can be difficult for me to see how the conduction band edge aligns.

[Anders Blom]

The central region is way too short, and that's precisely why it bends, it doesn't have enough material to screen towards the electrodes. Make each interface region 2-4x longer, then check again, if it's still curved you need even longer.