How to correct the dipole's effect on planar averaged potential?

Message

sjtu · #1 Post by **sjtu** » Thu Mar 19, 2009 7:58 pm

Hello,
My supercell is as below. the surfaces are A and B on two sides. So there is dipole across the system for the periodicity of the system. So the vassum level in the vacuum region is not flat. And now I am going to get the flat vaccum level on the B sides and the flat vacuum level on the A side.
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vac AAAABBBB vac
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There is one way I know can sovle the problem.
By setting the supercell like below:
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vac AAAABBBB vac BBBBAAAA vac
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But I want to use a small supercell to sovle the problem.
Is there anybody knowing how to set the INCAR to correct the potential?
Thank you so much.

#2 Post by **admin** » Fri Mar 20, 2009 3:44 pm

please set IDIPOL=3 (if the z-axis is pependicular to the slab) ; LDIPOL=.true. The dipole corrections will replace the slope of the potential in the vacuum (caused by the dipole moment across the slab by a {slightly smeared) step function in the middle of the vacuum, so the potential in the vacuum will be flat at each side of the slab (in a region sufficiently far away).

sjtu · #3 Post by **sjtu** » Sat Mar 21, 2009 12:15 am

Thank you. I will try it.