[Wien] About Phonon calculations

[Peter Blaha]

You don't need to go through VESTA, .....

I copy the procedure for FCC Si (it is for a student exercise, the 
computational parameters like k-points and rkmax are a bit low):

cd ~/WIEN2k; mkdir Si-phonon; cd Si-phonon
makestruct
Si,  F cell,  a=b=c=5.43 Ang, α=β=γ=90°; Si: 
(.125,.125,.125);(.875,.875,.875)
setrmt 3%
x supercell  (init.struct, 1x1x1, P-lattice)   	# phonopy can handle only P
cp init_super.struct Si-phonon.struct
edit Si-phonon.struct        		# label all atoms as Si1,2,3,4
init_lapw -b -numk 10 -rkmax 6  		# (batch mode)
phonopy --wien2k -c Si-phonon.struct -d --dim=“2 2 2”
mkdir 1;
cp Si-phonon.structS-001  1/1.struct
cd 1
init_lapw -b -numk 10   -rkmax 6     # (batch mode)
run_lapw -fc 0.02               # (optionally use some parallelization)
cp 1.scf ..
cd ..
phonopy --wien2k -f 1.scf
create band.conf with editor, containing the following information:
ATOM_NAME = Si
DIM = 2 2 2
PRIMITIVE_AXIS = 0.5 0.5 0.0   0.0 0.5 0.5   0.5 0.0 0.5
BAND = 0.5 0.5 0.5   0 0 0  0.5 0 0   0.5 0.5 0   0 0 0
BAND_LABELS = L G  X  K G
BAND_CONNECTION = .TRUE.
phonopy --wien2k -c Si-phonon.struct band.conf –p
save with: phonopy --wien2k -c Si-phonon.struct band.conf –p –s  #(band.pdf)

Am 15.09.2022 um 05:58 schrieb AJAY SINGH VERMA:
> Dear all,
> 
> I want to do phonon calculation to check the dynamical stability of my 
> system. To start the calculation, at first, I have optimized the 
> geometry (in conventional cell). To make a primitive cell of my 
> structure, I used VESTA as an interface to convert my wien2k structure 
> file to POSCAR (VASP) format. This POSCAR file I have used in phonopy to 
> generate primitive cell of my structure. Now I am not able to find any 
> way to convert back this primitive POSCAR file in wien2k format to 
> generate supercell of my structure. Now I have the following querries:
> 
> (a) Can I generate primitive cell of my structure directly without going 
> through the above mentioned procedure.
> 
> (b) How should I decide q-path (in phonon dispersion spectrum) of my system?
> 
> Based on my literature search, to do phonons, I need supercells 
> (generated through primitive cell) of my system. Am I following right 
> procedure or Is there any other way to do phonons in wien2k?
> 
> Thanks & regards
> 
> _______________________________________________
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-- 
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300
Email: peter.blaha at tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at
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