Wannier90 bands

[mtardieux]

Dear VASP Forum,

I have a question regarding a Wannier interpolation I'm performing at the interface between VASP and Wannier90.

In my calculation, I’m using the following orbital projections:
Mn: d
Sb: p
Te: p

My system contains 1 Mn, 2 Sb, and 4 Te atoms. Since SOC is included, this leads to a total of 46 Wannier functions.

However, the interpolation is not performing ideally, the figure is attached as reference.

I would like to remove the top two conduction bands (the two uppermost blue bands in the interpolation), without changing my chosen projections. In other words, having 44 bands in my interpolation, but while keeping my projections (Mn d, Sb p, Te p).

Here is my current .win file input:

Code: Select all

num_bands = 46
num_wann = 46

Begin Projections
Mn: d
Sb: p
Te: p
End Projections

exclude_bands: 1-12, 59-128

I’ve tried using the exclude_bands keyword to drop unwanted bands outside the relevant energy window, but I get this error "num_bands must be higher or equal to num_wann".

Is there a recommended way to do this?

Thanks a lot for your help!

Best regards,
Marie

[henrique_miranda]

I would like to remove the top two conduction bands (the two uppermost blue bands in the interpolation), without changing my chosen projections. In other words, having 44 bands in my interpolation, but while keeping my projections (Mn d, Sb p, Te p).

I fear this is not possible.
When you choose the initial projections you are also choosing the number of Wannier functions.
What you can do is to set only "px;py" (2 projections) instead of "p" (3 projections) per Sb for example.
You can also play with the d orbitals of Mn to get to 44 Wannier functions instead of 46.
But this can mean a lot of trial an error an in the end you might not even get a better Wannier interpolation of the band-structure.

If the initial guess for the Wannier orbitals is not particularly important to you you can try the SCDM method:
https://www.vasp.at/wiki/index.php/Cons ... CDM_method
in that case you only need to set:

Code: Select all

NUM_WANN=44
LSCDM=.TRUE.

Let me know if this helps!

[mtardieux]

Hi Henrique,
Thank you for your suggestions! I'll give them a try and let you know how it went