does anyone have experience with calculations involving the ESM method? Effective screening medium.

I am trying to study a PbTiO3 slab which is polarized in the z direction and I need to cut the coulomb interaction along the z direction. I have tried using large vacuum regions but this is not working and in the long run I reach the FFT limit.

I have seen that ESM provides a way to immerse the slab in an effective medium and can deploy different type of boundary conditions. One is vacuum-slab-vacuum and this is what I need. But here is where I get confused.

I need to prepare my slab with vacuum regions in the z directions. The question is, in this case how much vacuum do I need if the whole thing is supposed to be immersed in vacuum? What sort of convergence do I need to perform to figure out the needed vacuum region?



  • $\begingroup$ I gave my +1 long ago, but just wanted to check how things are going for you with this problem? Have you figured out the answer? Have you made any progress? Are you still working on it? Please update us! $\endgroup$ Feb 18, 2023 at 5:31
  • $\begingroup$ this is still an open problem for me and I have not found an answer. there is almost no information apart from the original articles of the ESM method and there is no best practices. the examples are for extremely simple cases that provide no information. For the moment I gave up on the method and I am looking at something else now. It is a shame because it looked like a good approach. $\endgroup$
    – lucian
    Feb 19, 2023 at 10:48
  • $\begingroup$ Since you didn't ping me with the @ character, I did not see your response. $\endgroup$ Dec 1, 2023 at 20:11
  • $\begingroup$ @NikeDattani sorry about that. I have been distracted by many other things but recently I have started to look into it again. I have found a few more pieces of info about his method. however I am unable to test them at the moment until my laptop returns from the repair shop. $\endgroup$
    – lucian
    Dec 3, 2023 at 11:06
  • $\begingroup$ Excellent. It was closed by Tyberius before your response to my last comment, but please do keep us updated after your laptop is fixed. If you find an answer, you can write a "custom" flag on this question, to have it reopened. $\endgroup$ Dec 5, 2023 at 19:31


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