Regarding "nband" value in lesson response function 1  [SOLVED]

Phonons, DFPT, electron-phonon, electric-field response, mechanical response…

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Seba Darshan
Posts: 63
Joined: Mon Feb 17, 2014 5:19 am

Regarding "nband" value in lesson response function 1

Post by Seba Darshan » Thu May 18, 2017 7:38 am

Dear Abinit users

I am trying to understand the abinit tutorial lesson on response function calculation 1 , "The ground state geometry of AlAs". In the input file trf1_1.in available in abinit/tests/tutorespfn/Input, the "nband" input variable has value as 4. I don't understand how the "nband" value was chosen as 4.

Can someone help me in this regard.
Any comments on my doubt are highly appreciated.

Thanks in advance
Seba

mverstra
Posts: 655
Joined: Wed Aug 19, 2009 12:01 pm

Re: Regarding "nband" value in lesson response function 1  [SOLVED]

Post by mverstra » Thu May 18, 2017 10:27 am

Hi Seba,

the code will give you a default number of bands which is number of electrons / 2 (for spin) + 10% or so. Here we set it by hand to get only the occupied bands (for an insulator this is fine). The number of valence electrons are 3 and 5 for the 2 species, so 8 / 2 = 4
Matthieu Verstraete
University of Liege, Belgium

Seba Darshan
Posts: 63
Joined: Mon Feb 17, 2014 5:19 am

Re: Regarding "nband" value in lesson response function 1

Post by Seba Darshan » Thu May 18, 2017 12:19 pm

mverstra wrote:Hi Seba,

the code will give you a default number of bands which is number of electrons / 2 (for spin) + 10% or so. Here we set it by hand to get only the occupied bands (for an insulator this is fine). The number of valence electrons are 3 and 5 for the 2 species, so 8 / 2 = 4


hai mverstra,

Thank you for clarifying my doubt.

Regards
Seba

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