[Wien] Top surface layer seems to be isolated from the rest of the system

[Laurence Marks]

Did you check:
a) The BVS, to ensure that you do not have a GIGO surface?
b) Whether the system has a decent gap or not -- I believe WO3 should be an
insulator.
c) Whether you are satisfying valence neutrality at the surface.

I expect you have a GIGO surface, 99.99% probability. You cannot just
create an oxide supercell and expect it to lead to a realistic surface.
Fixing layers won't help, and is flawed thinking.

GIGO.

_____
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody
else has thought", Albert Szent-Györgyi
www.numis.northwestern.edu

On Fri, Jun 25, 2021, 01:31 Dr. K. C. Bhamu <kcbhamu85 at gmail.com> wrote:

> Dear Wien2k Users,
>
> I am trying to relax the WO3 surface structure (1x1x5 with 15 Ang vacuum).
> The bulk structure crystallizes in  221 SG.
> Then I created the 1x1x5 layered structure and relaxed the top two layers
> with the bottom three layers kept fixed.
> I see after relaxation, the top layer detached from the system (the W-O
> bond length increased from 1.9 to 2.3 Ang), you can see from the PDF
> provided with this email.
> I have tried with QE as well and the same problem I faced there.
> I am wondering if someone has faced a similar experience and would like to
> share his/her experience with me to tackle this issue.
>
> I have used a different strategy: with U, with U, with dipole correction,
> without dipole correction, vacuum up to 30Ang.
>
> As the bulk system is a high symmetry system, is it the reason due to
> the symmetry? If so then how one can handle it?
>
> I am providing the required information here in the tar file  (PLEASE
> DOWNLOAD FROM HERE
> <https://urldefense.com/v3/__https://we.tl/t-0vedkrUS54__;!!Dq0X2DkFhyF93HkjWTBQKhk!Day7KZQBXQaPn8HGxSpldvOiJzObtS73z_8I17izzlA5ZmuvSj27rMzSsjCo-bt6MCzNAQ$>
> ).
>
> I would appreciate it if someone shares their experience with me.
>
> Regards
> Bhamu
>
>
>
>
>
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