Dear Laura,
usually it is not a problem, and it is a good strategy when converging wrt k points as gamma is present in all the centred grids. The only problem that can arise is that the wfs at gamma and at k points when the gap occurs have a different character so the parameter of convergence can be slightly different.
Best,
Daniele
Band gap convergence
Moderators: Davide Sangalli, andrea.ferretti, myrta gruning, andrea marini, Daniele Varsano
- Daniele Varsano
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Re: Band gap convergence
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/
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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Re: Band gap convergence
Hello Daniele,
Just to be sure, I calculated the values again at the direct gap point at both 200 bands (as converged at Gamma) and at 350 bands. Compared to the Gamma point, the difference between the values changes more or less 2x10-3.
200 the gap is 1.9761 and at 350 is 1,9674. So, I guess, it still converged also at this point, right?
Just to be sure, I calculated the values again at the direct gap point at both 200 bands (as converged at Gamma) and at 350 bands. Compared to the Gamma point, the difference between the values changes more or less 2x10-3.
200 the gap is 1.9761 and at 350 is 1,9674. So, I guess, it still converged also at this point, right?
Laura Caputo
Ph.D. Student
Université Catholique de Louvain
https://uclouvain.be/fr/repertoires/laura.caputo
Ph.D. Student
Université Catholique de Louvain
https://uclouvain.be/fr/repertoires/laura.caputo
- Daniele Varsano
- Posts: 3773
- Joined: Tue Mar 17, 2009 2:23 pm
- Contact:
Re: Band gap convergence
Dear Laura,
from your numbers the difference is about 9 meV which is a reasonable threshold.
Daniele
from your numbers the difference is about 9 meV which is a reasonable threshold.
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/
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/
-
- Posts: 88
- Joined: Sun Apr 11, 2021 3:02 pm
Re: Band gap convergence
Dear Daniele,
Thanks. I checked also for other systems and the differences are even lower so I guess that I could take that as converged values. Thanks again,
Laura
Thanks. I checked also for other systems and the differences are even lower so I guess that I could take that as converged values. Thanks again,
Laura
Laura Caputo
Ph.D. Student
Université Catholique de Louvain
https://uclouvain.be/fr/repertoires/laura.caputo
Ph.D. Student
Université Catholique de Louvain
https://uclouvain.be/fr/repertoires/laura.caputo