B doped diamond example

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tswang
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Joined: Wed Oct 12, 2016 1:40 am
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B doped diamond example

Post by tswang »

Dear users,

In the diamond example, the chosen dis_froz_max and dis_win_max are 7 and 15 eV, respectively.

Why do we choose the values? Why don't we choose 15eV for dis_froz_max since we are interested in the four valence band? If my nbnd=6, should I use dis_win_max=20?

What about n-type diamond? Should I choose 8 nbnd, and use dis_froz_max=19 and dis_win_max=30?

The band energy is shown below:
-7.95675 13.89078 13.89078 13.89078 19.55356 19.55356

Thank you!

Tianshi Wang
University of Delaware, DE, USA

sponce
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Posts: 616
Joined: Wed Jan 13, 2016 7:25 pm
Affiliation: EPFL

Re: B doped diamond example

Post by sponce »

Dear Tianshi,

You can plot the Wannier function and overlay them with the nscf bandstructure. The band should be quite close.
This is to show the disentanglement procedure. If you choose dis_froz_max 14 eV and have only 4 bands, then you Wannierized everything (so no disentanglement).

You could indeed impose dis_froz_max 14 eV for valence band only and dis_froz_max = 20 eV for conduction bands as well.

But in any case you have to make sure that the Wannier interpolation reproduces very closely the correct electronic and phonon bandstructure.

Best,

Samuel
Prof. Samuel Poncé
Chercheur qualifié F.R.S.-FNRS / Professeur UCLouvain
Institute of Condensed Matter and Nanosciences
UCLouvain, Belgium
Web: https://www.samuelponce.com

tswang
Posts: 14
Joined: Wed Oct 12, 2016 1:40 am
Affiliation:

Re: B doped diamond example

Post by tswang »

Hi Samuel,

Thank you for your reply! It is very helpful to me.

I chose (0 for dis_froz_max, 10 for dis_win_max) for p-type and (10, 16) for n-type based on my understanding. The interpolated band structure doesn't have notable change. Do you think it is fine?

This material is 3C-SiC. The band gap is around 10 eV. For n-type, only care the lowest conduction band.
Image

Best regards,

Tianshi

sponce
Site Admin
Posts: 616
Joined: Wed Jan 13, 2016 7:25 pm
Affiliation: EPFL

Re: B doped diamond example

Post by sponce »

Dear Tianshi,

This look good for the wannierization of the valence band indeed.

Maybe you can also make a zoom close to the VBM to be sure that the curvature (effective mass) is correct.

Best,

Samuel
Prof. Samuel Poncé
Chercheur qualifié F.R.S.-FNRS / Professeur UCLouvain
Institute of Condensed Matter and Nanosciences
UCLouvain, Belgium
Web: https://www.samuelponce.com

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