Phase transition under pressure?
Posted: Mon Oct 29, 2018 8:42 am
Hello everybody
I am trying to investigate properties of a perovskite compound, experimentally phase undergoes through transition at 4 GPa,
I also increase the pressure and I do relaxation to the unit cell for all pressures up to 10 GPa, but my structure keeps the same which is cubic (doesn't undergo phase transition)
see the input file please
optcell 2
prtcif 1
prtgeo 1
#tsmear 0.02
ndtset 10
strtarget1 -3.39892892272001E-05 -3.39892892272001E-05 -3.39892892272001E-05 0 0 0
strtarget2 -6.79785784544003E-05 -6.79785784544003E-05 -6.79785784544003E-05 0 0 0
strtarget3 -0.0001019679 -0.0001019679 -0.0001019679 0 0 0
strtarget4 -0.0001359572 -0.0001359572 -0.0001359572 0 0 0
strtarget5 -0.0001699464 -0.0001699464 -0.0001699464 0 0 0
strtarget6 -0.0002039357 -0.0002039357 -0.0002039357 0 0 0
strtarget7 -0.000237925 -0.000237925 -0.000237925 0 0 0
strtarget8 -0.0002719143 -0.0002719143 -0.0002719143 0 0 0
strtarget9 -0.0003059036 -0.0003059036 -0.0003059036 0 0 0
strtarget10 -0.0003398929 -0.0003398929 -0.0003398929 0 0 0
#relaxation
ionmov 2
ntime 100
tolmxf 5.0d-6
dilatmx 1.1
#Cell and atoms definition
acell 3*6.0045791044 Angstr
rprim 0.0 0 1
1 0.0 0
0 1 0
ntypat 3 natom 5 typat 1 2 3 3 3
xangst 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00
3.0022903116E+00 3.0022903116E+00 3.0022903116E+00
3.0022903116E+00 0.0000000000E+00 3.0022903116E+00
3.0022903116E+00 3.0022903116E+00 0.0000000000E+00
0.0000000000E+00 3.0022903116E+00 3.0022903116E+00
znucl 55 82 35 nband 40
#Basis definitions
ecut 45
ecutsm 0.5
pawecutdg 100
#SCF cycle parameters
tolvrs 1.0d-15
nstep 200
iscf 5
#K-points and sym
#nsym 0
occopt 1
ngkpt 6 6 6
nshiftk 4
shiftk 0.5 0.5 0.5
0.5 0.0 0.0
0.0 0.5 0.0
0.0 0.0 0.5
#I/O parameters
prtwf 1 prtden 0 prteig 0
getwfk -1
timopt 2
Any help please ?
Nawzad
I am trying to investigate properties of a perovskite compound, experimentally phase undergoes through transition at 4 GPa,
I also increase the pressure and I do relaxation to the unit cell for all pressures up to 10 GPa, but my structure keeps the same which is cubic (doesn't undergo phase transition)
see the input file please
optcell 2
prtcif 1
prtgeo 1
#tsmear 0.02
ndtset 10
strtarget1 -3.39892892272001E-05 -3.39892892272001E-05 -3.39892892272001E-05 0 0 0
strtarget2 -6.79785784544003E-05 -6.79785784544003E-05 -6.79785784544003E-05 0 0 0
strtarget3 -0.0001019679 -0.0001019679 -0.0001019679 0 0 0
strtarget4 -0.0001359572 -0.0001359572 -0.0001359572 0 0 0
strtarget5 -0.0001699464 -0.0001699464 -0.0001699464 0 0 0
strtarget6 -0.0002039357 -0.0002039357 -0.0002039357 0 0 0
strtarget7 -0.000237925 -0.000237925 -0.000237925 0 0 0
strtarget8 -0.0002719143 -0.0002719143 -0.0002719143 0 0 0
strtarget9 -0.0003059036 -0.0003059036 -0.0003059036 0 0 0
strtarget10 -0.0003398929 -0.0003398929 -0.0003398929 0 0 0
#relaxation
ionmov 2
ntime 100
tolmxf 5.0d-6
dilatmx 1.1
#Cell and atoms definition
acell 3*6.0045791044 Angstr
rprim 0.0 0 1
1 0.0 0
0 1 0
ntypat 3 natom 5 typat 1 2 3 3 3
xangst 0.0000000000E+00 0.0000000000E+00 0.0000000000E+00
3.0022903116E+00 3.0022903116E+00 3.0022903116E+00
3.0022903116E+00 0.0000000000E+00 3.0022903116E+00
3.0022903116E+00 3.0022903116E+00 0.0000000000E+00
0.0000000000E+00 3.0022903116E+00 3.0022903116E+00
znucl 55 82 35 nband 40
#Basis definitions
ecut 45
ecutsm 0.5
pawecutdg 100
#SCF cycle parameters
tolvrs 1.0d-15
nstep 200
iscf 5
#K-points and sym
#nsym 0
occopt 1
ngkpt 6 6 6
nshiftk 4
shiftk 0.5 0.5 0.5
0.5 0.0 0.0
0.0 0.5 0.0
0.0 0.0 0.5
#I/O parameters
prtwf 1 prtden 0 prteig 0
getwfk -1
timopt 2
Any help please ?
Nawzad