GW0 calculations

Concerns issues with computing quasiparticle corrections to the DFT eigenvalues - i.e., the self-energy within the GW approximation (-g n), or considering the Hartree-Fock exchange only (-x)

Moderators: Davide Sangalli, andrea.ferretti, myrta gruning, andrea marini, Daniele Varsano

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amolina
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GW0 calculations

Post by amolina » Tue Dec 16, 2014 12:49 pm

Dear all,

I noticed we have the variable GWoiter. How is exactly done the self-consistent in the GW? Yambo updates eigenvalues and occupancies? only eigenvalues?

Cheers,

Alejandro.
Alejandro Molina-Sánchez
Institute of Materials Science (ICMUV)
University of Valencia, Spain

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Daniele Varsano
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Re: GW0 calculations

Post by Daniele Varsano » Tue Dec 16, 2014 1:39 pm

Dear Alejandro,
Self consistency it is not contained in the GPL version.
Hopefully it will be in the next release. It update both eigenvalues and occupancies.
Hopefully it will be released soon.
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/

Khaled
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Joined: Fri Apr 10, 2015 10:11 am
Location: South Africa

Re: GW0 calculations

Post by Khaled » Tue Jun 16, 2015 8:58 am

Hello Developer,

I did DFT calculation (scf and nscf) in Quantum Espresso and I selected k point 4 4 4 1 1 1 , and then I went through GW and BSE calculation by using Yambo everything went very well, but when I used k point 4 4 4 0 0 0 everything went wrong. I found Direct and in direct band gap changed totally by very high factor and then GW calculation stopped and BSE as well. I have attached report and log files for both. I am waiting for your a valuable suggestion. Thank you in advance.

Best regards,

Khaled.
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Khaled Shehata,
PhD Student,
School of Physics,
Witwatersrand University

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Daniele Varsano
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Re: GW0 calculations

Post by Daniele Varsano » Wed Jun 17, 2015 9:02 am

Dear Khaled,
it looks you have a netcdf problem (input/output), which is not easy to understand what is going on.
First: are you suer you need to calculate corrections for 160x24=3840 states? You can reduce the number of bands in %QPkrange calculating the bands across the Fermi levels.
Next, the gap reported by yambo in:

Code: Select all

 [02.05] Energies [ev] & Occupations
it is the KS gap and it comes from the QE calculations. What yambo does is to read the QE calculation and report it there. Check the QE outputs and try to understand what is going on at KS level.

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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