Yambo with B2LYP

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Joe_Page_93
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Joined: Tue Dec 13, 2022 12:33 pm
Location: Loughborough University

Yambo with B2LYP

Post by Joe_Page_93 » Tue Dec 13, 2022 1:48 pm

Hi,

I am using Quantum Espresso v7.0, and Yambo 5.0.4.

I am trying to calculate the band structure of a material using a hybrid function. I know that 'input_dft = "HSE",' doesn't work correctly with yambo, so i have been using 'input_dft = "b3lpv1r"'. After the SCF calculation has finished, and converged, i can use p2y to generate the SAVE folder and initialise it using the yambo command.

However, when i try to generate the input file for a Hartree Fock calculation (yamvo -x -F hf.in), the file generated is empty (apart fro the yambo header). If I input the parameters it manually, the output file isn't correct, given other HF calculations I have done.

Is there a step i am missing? As far as i am aware i am not missing any steps (as I cannot perform the nscf calc), But if anyone has any incite into this issue, please let me know.

Thanks you.

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Daniele Varsano
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Re: Yambo with B2LYP

Post by Daniele Varsano » Tue Dec 13, 2022 2:58 pm

Dear Joe_Page_93,

first, let me ask you to sign your post with your name and affiliation, this is a rule of the forum! You can do once for all by filling your signature in the user profile.
If the p2y run successfully, most probably it is not a problem of the hybrid functional, but there should be something else preventing working correctly.

Can you post in attachment your setup file r_setup? You can attach to the post by renaming it, e.g. r_setup.txt

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/

Joe_Page_93
Posts: 5
Joined: Tue Dec 13, 2022 12:33 pm
Location: Loughborough University

Re: Yambo with B2LYP

Post by Joe_Page_93 » Tue Dec 13, 2022 3:10 pm

Hi Daniele,

Okay, Its good that is not a hybrid problem as I have been trying to figure how to do an nscf calculation for a while now.

Sure. I have attached the r_setup file as suggested. Hope it helps.

Thank you again.
Joe
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Dr. Joseph A. Page, Research Associate, Department of Physics, Loughborough University, UK

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Daniele Varsano
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Re: Yambo with B2LYP

Post by Daniele Varsano » Wed Dec 14, 2022 9:08 am

Dear Joseph,

the problem is related to the fact your K grid is not seen as uniform by Yambo:

Code: Select all

[WARNING][RL indx] 2 equivalent points in the rlu grid found
 [RL indx] X grid is not uniform. Gamma point only.

 [WR./SAVE//ndb.kindx]-----------------------------------------------------------
  Fragmentation                                    : no
  Polarization last K                              :  26
  QP states                                        :   1  26
 X grid is uniform                                : no 
Check your unit cell geometry and k point grid in the scf QE file.
If all seems OK, you can try to remove the ndb.* files in the SAVE directory and repeat the setup calculation, adding the following keyword in the input file:

Code: Select all

NoDiagSC
and see if this solves the problem.

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/

Joe_Page_93
Posts: 5
Joined: Tue Dec 13, 2022 12:33 pm
Location: Loughborough University

Re: Yambo with B2LYP

Post by Joe_Page_93 » Wed Dec 14, 2022 11:26 am

Hi Daniele,

So in my scf calculation i am using an automatic k-point grid, but i am also using ibrav = 0, as my unit call cannot be defined by the build in system. Could that be the reason behind the non-uniform K grid?

I re-ran the p2y command and check the SAVE folder, and none of the files where ndb.*. They where all ns.* (there was one ns.db1, but i assume thats not what you are on about). Is there something i have missed in the steps?

Thank you again,
Joe
Dr. Joseph A. Page, Research Associate, Department of Physics, Loughborough University, UK

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Daniele Varsano
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Re: Yambo with B2LYP

Post by Daniele Varsano » Wed Dec 14, 2022 11:48 am

Dear Joe,
but i am also using ibrav = 0, as my unit call cannot be defined by the build in system. Could that be the reason behind the non-uniform K grid?
Yes, it is possible.

I re-ran the p2y command and check the SAVE folder, and none of the files where ndb.*
The ndb* file are created by Yambo, you should delete the ones created previously by the setup.
If you run p2y in a different directory, it is ok. it is important you start the setup from scratch.

Next, create a setup file using:

Code: Select all

>yambo -i -V all 
and activate the NoDiagSC keyword, which is commented by default, then run yambo:

Code: Select all

>yambo
Check in the report file if the grid is seen as uniform.
If it is not working, there is not much to do than find a way to define a unit cell using a bravais lattice.

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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