Yambo Community Forum

Dear Developers,

I used ypp to interpolate the bands from QE calculation for a spin polarized system and got some weird output compared to the band structure I got from QE's `bands.x` and `plotbands.x`. What I did was simply generate the SAVE database using `p2y` from a nscf calculation, and then used 'ypp -s b' to get the input file. The spin up channel seems good, but the spin down is quite off. So I wonder whether I generate the SAVE database incorrectly which may affect my other calculations.

I also attached my nscf and ypp input file here for you inspection.

Thank you!

Dear Khoa,

the issue is that there is a missing conversion factor in the values of the spin down channel.
Just multiply the energies by 27.2114 (the conversion factor from Hartree to eV) and you should get the correct value.

Best,
D.

P.S.: this could give problems can you try changing it to

Davide Sangalli wrote: ↑Fri Mar 25, 2022 9:08 am Dear Khoa,

the issue is that there is a missing conversion factor in the values of the spin down channel.
Just multiply the energies by 27.2114 (the conversion factor from Hartree to eV) and you should get the correct value.

Best,
D.

P.S.: this could give problems

Code: Select all

%BANDS_kpts                      # K points of the bands circuit
0.000000  |0.000000  |0.000000  |  !G
0.500000  |0.000000  |0.000000  |  !M
0.333333  |0.333333  |0.000000  |  !K
0.000000  |0.000000  |0.000000  |  !G
%

can you try changing it to

Code: Select all

%BANDS_kpts                      # K points of the bands circuit
0.000000  |0.000000  |0.000000  |  #G
0.500000  |0.000000  |0.000000  |  #M
0.333333  |0.333333  |0.000000  |  #K
0.000000  |0.000000  |0.000000  |  #G
%

Hi Davide,

Thank you for your reply. Multiply by the conversion factor does give the good bands. However, I tried your suggestion to the ypp input, but it did not fix it.

It seems to be just about 'ypp' interpolation, so do you think the database is good to do GW-BSE for the spin-flip channel?

Best,

Dear Khoa Le

the missing factor is not related to the input file. You can safely proceed with GW/BSE calculations, however, it is not clear to me what do you mean by spin-flip channel.

Best,
Daniele

Daniele Varsano wrote: ↑Tue Mar 29, 2022 9:15 pm
You can safely proceed with GW/BSE calculations, however, it is not clear to me what do you mean by spin-flip channel.

Hi Daniele,

Thank you for the reply and my apologize for the late respond.
What I mean is the calculation of magnon using BSEprop = "magn". So can I assume it is still safe in this case then?

Khoa

Dear Khoa,

most probably yes, even if I'm not an expert in this kind of calculation.

Best,
Daniele

Daniele Varsano wrote: ↑Tue Apr 05, 2022 7:28 am Dear Khoa,

most probably yes, even if I'm not an expert in this kind of calculation.

Best,
Daniele

Thank you for your help!