band structure changed after HF calculation

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leeru
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Joined: Mon Oct 03, 2022 4:00 pm

band structure changed after HF calculation

Post by leeru » Wed Dec 07, 2022 3:49 am

Dear all
when I use QE to study the band structure of Ca6N2AsSb, it is direct bandgap located at k point 1 (the gamma point), however, after the HF calculation it is still direct bandgap, but it shifted to point 3 (not the gamma point), anyone can help, see the attached screenshot.
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Dr. Ru Li
College of Optoelectronic Engineering
Chongqing Univerity, China
https://www.cqu.edu.cn

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Daniele Varsano
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Joined: Tue Mar 17, 2009 2:23 pm
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Re: band structure changed after HF calculation

Post by Daniele Varsano » Wed Dec 07, 2022 12:03 pm

Dear Leeru,

can you please sign your post with your full name and affiliation? This is a rule of the forum and you can do once for all by filling your signature in the user profile.

Not easy to understand from the screenshot only, I suggest you to inspect and compare all the energies in the BZ and see how the band structure has changed.
Please note that the HF occupation report make sense only if you have calculated the HF energies for all the k points and bands around the Fermi energies.

Best,

Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

leeru
Posts: 2
Joined: Mon Oct 03, 2022 4:00 pm

Re: band structure changed after HF calculation

Post by leeru » Wed Dec 07, 2022 2:37 pm

Dear Daniele

Thank you for your reply, I have updated my signature, I don't do the HF calculation for all the points around fermi level but only one point, maybe the result is not sensible.

Regards
Ru
Dr. Ru Li
College of Optoelectronic Engineering
Chongqing Univerity, China
https://www.cqu.edu.cn

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Daniele Varsano
Posts: 3773
Joined: Tue Mar 17, 2009 2:23 pm
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Re: band structure changed after HF calculation

Post by Daniele Varsano » Wed Dec 07, 2022 3:42 pm

Dear Ru,
in this case, have a look at the HF corrections you are interested in without looking at the gap report.
The latter is not the correct one if all the energies have not been corrected consistently.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

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