I am solving the Poisson equation for heterojunction using Fortran90. I use the SOR algorithm to arrive at the potential profile.
I see the weird behavior where the error (the difference between the $n$-th and $(n-1)$-th iteration of the solution) abruptly falls to zero when the error reaches 1e-7 range. Is this behavior expected?
Also, the solution is depending weakly on the choice of the mesh, e.g. potential profiles are off by about 0.02 eV when I choose a coarser mesh. Is this behavior to be expected?
Let me know if I need to provide any additional details.