Yambo Community Forum

Dear all
I want to plot the GW bandstructure, I did the calculation GW approximation by yambo -g n -p p.
I got a file with the name o.qp.
1) Can I get bandstructure from that file ? if yes, how?
2) Can I know the value of gap without plotting bandstructure ?
Thanks
Fatima Zahra

Dear Fatima,
in the o.qp you have all you need for the band structure. As you can read in the legend it is ordered as: Eo is the KS energy, E-Eo is the GW correction, Sc is the correlation part of the self-energy and you not need it for the band structure.
In order to plot the band structure, e.g. with gnuplot you just have to edit a little bit the file in order to put in the form: If you know the index (K-point and Band) corresponding to the valance maximum and conduction minimum at KS level you can directly look at the corresponding GW correction in the o.qp file.

Cheers,
Daniele

Thank you very match
I have another question, What is the role of ypp ?
I want to know is that the the bandstructure, that I found in o.qp, calculate along the Gamma-X-Gamma ?
Thanks for all

Dear Fatima,

I have another question, What is the role of ypp ?

Ypp is a post processing tool, for plot and analysis of results generated by yambo.
you can find its functionality here.
A short description on how generate input files can be found by typing ypp -H

I want to know is that the the bandstructure, that I found in o.qp, calculate along the Gamma-X-Gamma ?

There is not an o.qp in attachment, anyway the o.qp reports indexes, K-points and bands are assigned via the variable
QPkrange, for example: with these settings you are asking to yambo to calculate QP energies for 32 bands for the first 5 K-points. As the K-points are indicated by indexes you have to check in tour report to which K-points do they correspond.

Hope it helps.
Daniele

Thanks a lot
If I want to calculate the bandstructure in gamma-X-Gamma, I can use point K crystale in SCF and NSCF for specify the points.

Right,
you have to select your K-points in the quantum espresso ground state calculations first. Yambo will calculate QP correction in that points.

Best,

Daniele

Hi
I plotted graphene bandstructure but the results are not good, I used Kpoint automatic,
After I run scf and nscf with Kpoints crystale but yambo doesn't run with crystal points k. I read in ypp tutorial that ypp can plot the structureband and dos.
Can I use this command for plotting bandstructure for specify the points or dos?
Thanks

Dear Fatima,
sorry but I do not understand what is exactly the problem you are reporting. Yambo needs an uniform k-point grid, and it is quite independent on how you generate it with quantum espresso. What it is important is to set in the input of qe the flag: Next, yes you can plot dos, interpolate band structures and plot it with ypp, see the examples in the webpage.
Best,

Daniele

I used force_symmorphic=.true. and collect_wf=.true. in input scf and nscf, but the problem in input yambo, I have only one Gvector in input yambo. I changed this variable manually but it doesn't work.
I'll plot dos by using ypp and I will try again for plotting bandstructure.
thank you for your help

Dear Fatima,
if you do not post your inputs/outputs/reports it is nearly impossible to help you.
Cheers,
Daniele