Dear all,
I studied the total energy variation versus volume of the GaN and GaBi
cristals, in both Zinc-blenbe au wurtzite structure. my calculation
demonstrates that for the GaBi material the Zinc-blende structure is the must
stable, while the wurtzite is the fundamental structure for the GaN material
which is in great agreement whith the experimental results. Aiming the
determination of the phase concentration variation, I also investigated the
total energy variation of the GaNBi alloys for different concentration of the
Bi element for both noted structures. During on calculation we were waiting for
a phase transition from wurtzite to Zinc-blende structures follwing the Bi
concentration increase, which is not confirmed by our main calculation fact:
We found that in fast step phase transition was from wurtzite to zinc-blende,
then retured to wurtzite then to Zinc-blende increasing the concentration of
Bi.
My input is below:
Zinc-blende structutre:
&control
calculation='relax'
restart_mode='from_scratch',
tstress = .true.
tprnfor = .true.
prefix='810-28',
pseudo_dir = '/home/projet/pseudo/',
outdir='/home/projet/tp/'
/
&system
ibrav= 1, celldm(1) =9.00, nat= 8, ntyp= 3,
ecutwfc =50.0, ecutrho = 200.0,
/
&electrons
diagonalization='david'
conv_thr = 1.0e-6
mixing_beta = 0.6
/
&ions
ion_dynamics='bfgs'
/
ATOMIC_SPECIES
Ga 69.726 Ga.pz-bhs.UPF
n 14.0067 n_pz.upf
bi 208.980 bi_pz.upf
ATOMIC_POSITIONS (crystal)
Ga 0.00000000 0.00000000 0.00000000
Ga 0.50000000 0.50000000 0.00000000
Ga 0.50000000 0.00000000 0.50000000
Ga 0.00000000 0.50000000 0.50000000
bi 0.25000000 0.25000000 0.25000000
bi 0.75000000 0.75000000 0.25000000
n 0.75000000 0.25000000 0.75000000
n 0.25000000 0.75000000 0.75000000
K_POINTS (automatic)
5 5 5 1 1 1
Wurtzite structutre:
&control
calculation='relax'
restart_mode='from_scratch',
tstress = .true.
tprnfor = .true.
prefix='5750-28',
pseudo_dir = '/home/projet/pseudo/',
outdir='/home/projet/tp/'
/
&system
ibrav= 4, celldm(1) =6.10, celldm(3) =3.28, nat= 8, ntyp= 3,
ecutwfc =50.0, ecutrho = 200.0,
/
&electrons
diagonalization='david'
conv_thr = 1.0e-6
mixing_beta = 0.4
/
&ions
ion_dynamics='bfgs'
/
ATOMIC_SPECIES
Ga 69.726 Ga.pz-bhs.UPF
n 14.0067 n_pz.upf
bi 208.980 bi_pz.upf
ATOMIC_POSITIONS (crystal)
Ga 0.00000000 0.00000000 0.00000000
Ga 0.33333333 0.66666667 0.23787476
Ga 0.00000000 0.00000000 0.47574952
Ga 0.33333333 0.66666667 0.71362428
bi 0.00000000 0.00000000 0.17840607
bi 0.33333333 0.66666667 0.41628083
n 0.00000000 0.00000000 0.65415559
n 0.33333333 0.66666667 0.89203034
K_POINTS (automatic)
6 6 2 1 1 1
Could you please give me some suggestions?
Thank you in advance.
ALAYA Ramzi
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