[QE-users] PbTiO3 slab in vacuum with assume_isolated='2D'

[Lucian D. Filip]

I am not sure if the picture I sent will be seen by someone since it 
doesn't appear here. I don't know what is the practice on this mailing 
list to show pictures.

On 24-Jun-24 1:24 PM, Lucian D. Filip wrote:
>
> Sorry, for some reason the image was not attached to the message.
>
> On 24-Jun-24 1:09 PM, Lucian D. Filip wrote:
>>
>> Hello,
>>
>> I am looking at a PbTiO3 slab in vacuum. The slab is in a polarized 
>> state and I am trying to obtain the Hartree potential with the dipole 
>> correction applied. I have seen that the assumed_isolated = '2D' 
>> option should do just that. However, I do not understand the result I 
>> am getting. In the attached picture I have plotted the Hartree 
>> potential averaged along the z axis, for the polarized state and the 
>> centro-simmetric state with polarization zero.
>>
>> The slab is 5 PTO unit cells thick and there are 20 Angstroms of 
>> vacuum on each side. The vacuum region is well above the requirements 
>> of assume_isolated ='2D'. Can anyone explain two things:
>>
>> 1) why are there two regions in vacuum looking like a staircase.
>>
>> 2) why is there an electric field still present?
>>
>>
>> The weird artefacts at the edges of the supercell are due to the 
>> averaging procedure (i am still working on it, not sure where it is 
>> coming from).
>>
>>
>> Best regards,
>>
>> Lucian
>>
>>
>> -- 
>> Dr. Lucian Dragos Filip
>> National Institute of Materials Physics
>> Atomistilor str. 405A, PO Box MG. 7
>> Magurele, 077125
>> Bucharest, Romania
>> E-mail:lucian.filip at infim.ro
>> Website:https://lucianfilip.wordpress.com/
> -- 
> Dr. Lucian Dragos Filip
> National Institute of Materials Physics
> Atomistilor str. 405A, PO Box MG. 7
> Magurele, 077125
> Bucharest, Romania
> E-mail:lucian.filip at infim.ro
> Website:https://lucianfilip.wordpress.com/

-- 
Dr. Lucian Dragos Filip
National Institute of Materials Physics
Atomistilor str. 405A, PO Box MG. 7
Magurele, 077125
Bucharest, Romania
E-mail:lucian.filip at infim.ro
Website:https://lucianfilip.wordpress.com/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20240624/a5dd6d4b/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: CzGEFGLD0ABkp84I.png
Type: image/png
Size: 121527 bytes
Desc: not available
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20240624/a5dd6d4b/attachment.png>