Yambo Community Forum

Dear All,

I have been trying to calculate band strcutures of Al with real-axis GW.

However, the conduction bands calculated by real-axis GW seem to be strange (not smooth).

The band structure is attached (Al_bands_Real_axis_GW.png).

I tried to change some paramters (k-points, NGsBlkXd, BndsRnXd, ETStpsXd and so on),
but the results was not improved.

Are there any inappropriate parametes in my input files?

All the input and output files are attached.

Any suggestions are appreciated.

Note that:

The initial wave functions were generated by Quantum Espresso ver.5.1.1.

Yambo was compiled with intel compiler version 11.1.

Both of OpenMP and OpenMPI swicthes were turned on.

Drude term (DrudeWXd), which was calculated by Wien2k, was included.

I did not use "noinv = true" in QE because there are spatial inversions in Al.

Best regards

Kosuke Nakano.

Dear Kosuke,

Most probably there is not any problem with your GW calculations, but it is the interpolator which it happens it has problem.
You can try to play a bit with the parameters of interpolator, but not guaranteed it will solve the problem.
You can try the following:
See if it changes something by setting:
or other thing to try is to use more interpolation neighbours, more than 1 try to raise the Shellfac.

Try to use a regualr mesh: see this post:
viewtopic.php?f=9&t=898&p=4003&hilit=INTERPGrid#p4003

Hope it helps,

Daniele

Dear Daniele

Thank you for your prompt reply!
Unfortunately, None of these options improved the band structures ...

Try to use a regular mesh: see this post:
viewtopic.php?f=9&t=898&p=4003&hilit=INTERPGrid#p4003

I assumed that regular mesh was necessary only for DOS calculation.
What is appropriate values in my case?

I also searched for "lpfac" in src/modules/mod_interpolate.F, but I could not find the valuable.
It has been already obsolete value, hasn't it?

Best regards.

Kosuke Nakano

Dear Kosuke,

sorry, in the previous post the syntax was wrong:
The correct one is: or Try to see if this improve the band structure.

For the regular mesh, you need to try different values of the grid.

As a last option, it is possible to use the WanT code for band interpolation,
http://www.wannier-transport.org/wiki/i ... /Main_Page
as it can read the QP outputs produced by Yambo.
May be Andrea can add here some hint on how to do that in the case it is not documented in the website.

lpfac is defined here:
ypp/init_ypp/ypp_init.F

Best,
Daniele

Dear Kosuke,

just a quick follow up on the possibility to use WanT to interpolate yambo bands.
The interface has been coded in the development version of WanT but not yet released.
In case, I can provide a pre-release version of the code, though the next official release should be coming soon.

take care
Andrea

Dear Daniele,

Thank you for your prompt reply!

I tried the options:


and


Unfortunately, they did not improve the band structures as attached files.

The results did not change when I set:

lpfac is defined here:
ypp/init_ypp/ypp_init.F

Thanks. I noticed that lpfac has already been defined as 20_SP.
So, I did not change the value.

Best regards.

Kousuke Nakano.

------------------------------------------------------------------

Dear Andrea,

Thank you for your suggestion!

just a quick follow up on the possibility to use WanT to interpolate yambo bands.
The interface has been coded in the development version of WanT but not yet released.
In case, I can provide a pre-release version of the code, though the next official release should be coming soon.

As mentioned above, I could not improve the band structures.

Could I use the interpolation tools of WanT?

Best regards.

Kousuke Nakano.