MgB2 example

[arnabmajumdar]

Hi,
I am absolutely new to QE and EPW. I ran the PWSCF and PH examples successfully, however, when I am running the MgB2 example exactly as it is, although I don't have errors, I am getting results which are very different from the graphical examples given on the website. I understand the example is run for 25K while the illustrations on the website are for 10,38 and 43K, but the results are quite different. The nature of the graphs are similar but the magnitudes are not. Is this expected?

Thanks,
Arnab

[roxana]

Dear Arnab,

Please take a look at the following topic where your question has been addressed:

viewtopic.php?f=6&t=47

Best,
Roxana

[roxana]

Hi,

If you want to reproduce the plots given on the website you need to use the input parameters described in the EPW paper:

http://www.sciencedirect.com/science/ar ... 5516302260

The input variables provided in the examples are only meant to show how to run specific calculations and they are far from being the converged values.

Best,
Roxana

[arnabmajumdar]

Thank you very much. I will try it right away.

Best,
Arnab

[arnabmajumdar]

Hi,
Sorry for being late. I had performed the MgB2 example as given in the examples. Everything had matched back then.
However, I realized I never asked a question that had been bothering me. That is, what is the logic behind choosing the K points in the nscf_epw.in file? 27 K-points have been listed along with their weights. But they are not equivalent to the K-points used for the SCF calculcations.
How are they chosen?

Thanks,
Arnab

[roxana]

Hi,

The 27 k-points correspond to a uniform 3x3x3 k-mesh.

Best,
Roxana