Geometry Relaxation with E-Field

[bhackl]

Hi all,
I´ve noticed, that some other people already asked this question, but I couldn´t find a sufficient answer.
I want to perform a geometry relaxation under the influence of an electric field.
However, the EFIELD tag does not change the relaxation. When I tried using DIPOL corrections, there have been some changes, but the overall relaxation doesn´t change for different values of EFIELD.
I tried the same with EFIELD_PEAD but had no success either.

Is there a way to perform a geometry relaxation under the influence of an electric field?

Thank you

[pedro_melo]

Dear bhackl,

I think this forum post might help you with your issue Electric field contribution to forces with EFIELD_PEAD. Did you set LPEAD_RELAX=T in your INCAR?

If you did and it is still not performing as it should, could you provide me with the input files (INCAR, KPOINTS, POTCAR, POSCAR) and output files (OUTCAR and standard output) where this issue is present? Preferably with the smallest possible system that still gives you this error.

Kind regards,
Pedro

[bhackl]

Dear Pedro,
thank you very much for your response.
I set the INCAR as described in the post you´ve linked.
When I change the value of EFIELD_PEAD the resulting CONTCAR doesn´t change. Shouldn´t the relaxed structure be different for different values of an electrical field (e.g. EFIELD_PEAD = 0.0 0.0 0.01 and 0.0 0.0 0.001)

I´ve attached the input files I´ve used.

Thank you

[pedro_melo]

Dear bhackl,

Thanks for the feedback. I will have a look at your issue.

Best,
Pedro

[bhackl]

Dear Pedro,

what I´m wondering about is, that there´s no wiki entry about the tag "LPEAD_RELAX".
Could you please give me an explanation of what this tag exactly does?

thank you.
Kr,

[pedro_melo]

Dear Kr,

My apologies, I am not an expert on the issue, so I had to do some research on the topic.

From what I can gather, VASP is able to perform calculations with an external electric field on 2d structures, not on bulk systems, which is your case. The reason for this is that you need sufficient vacuum for VASP to be able to deal with the non-periodic electric field in a periodic system. You can see it here too.

If you do use a slab configuration, then it's is the EFIELD tag that you must use in your INCAR in order to activate the electric field, not EFIELD_PEAD. The latter is used only for the evaluation of response properties.

Do have a look at the thread and the links I posted and let me know if you have more questions.

Kind regards,
Pedro