Hello,<div> </div><div>I am using the Martyna-Tuckerman (MT) 2D Poisson solver for a ZnO slab model. With a vacuum buffer of approximately 25 Å or larger, I observe a flat region in the 2D-averaged Hartree potential along the non-periodic Z-direction.However, right at the very edge of the simulation box, a non-flat artifact appears, which consistently matches the number of layers in the slab. I have tried varying the CUTOFF, REL_CUTOFF, box size, dipole correction, and MT REL_CUTOFF, but this behavior persists.Could you please advise if there is a way to fix this boundary artifact (still using MT P solver), and whether this artifact affects the calculated electronic properties of the slab? I have attached some of the graphs in this mail.Thank you for your guidance.Best regards,Samira<img alt="10layer.png" width="534px" height="270px" src="cid:7c5eb0d9-ba32-43aa-a891-de79e62b67de" /><img alt="5Layer.png" width="534px" height="409px" src="cid:6498cd98-1d87-43e0-a92f-5d5c55422b1a" /></div> -- You received this message because you are subscribed to the Google Groups "cp2k" group. To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+unsubscribe@googlegroups.com">cp2k+unsubscribe@googlegroups.com</a>. To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/f39d5b61-11e8-4614-b454-ced2235974cen%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/f39d5b61-11e8-4614-b454-ced2235974cen%40googlegroups.com</a>.