In the case of Al, I realized that optimizing the lattice parameter using GGA works better than LSDA. To do so, and to employ GGA, I use the xctype command and set it to (20,0,0). There doesn't seem to be any problem when I use task 0 to calculate the ground state energy, but when I attempt to run my phonon superconductivity file, it presents the error "Error(fxcifc): response function unavailable for fxctype 20 0 0".
I consulted the manual and noticed that the default value for fxctype, which is -1, prompts the system to use the (f xc) exchange-correlation functional based on my xctype value "−1 fxc defined by xctype". I'm trying to understand what this error means and am looking for solutions to run my case in GGA for phonon calculations.
plot1d
4 200 : nvp1d, npp1d
0.0 0.0 0.0 : vlvp1d
0.5 0.5 0.0
1.0 0.0 0.0
0.5 0.0 0.0
i have to mention that it dos not have problem with LSDA before i set sctype to (20,0,0)
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There are two ways of calculating phonons in Elk. The first is using density functional perturbation theory (DFPT) and the second is with finite differences in a supercell which contains the q-vector. These are tasks 205 and 200, respectively.
Currently, DFPT only works with LDA. The finite differences method will work with most other exchange-correlation functionals available in Elk.
Regards,
Kay.
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Hi kay,
thank you for your answer.
where can i read about the exact way these 2 methods(DFPT, SUPERCELL) work to calculate the dynamical matrix?.
Regards,
Farhad
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hello everyone,
In the case of Al, I realized that optimizing the lattice parameter using GGA works better than LSDA. To do so, and to employ GGA, I use the xctype command and set it to (20,0,0). There doesn't seem to be any problem when I use task 0 to calculate the ground state energy, but when I attempt to run my phonon superconductivity file, it presents the error "Error(fxcifc): response function unavailable for fxctype 20 0 0".
I consulted the manual and noticed that the default value for fxctype, which is -1, prompts the system to use the (f xc) exchange-correlation functional based on my xctype value "−1 fxc defined by xctype". I'm trying to understand what this error means and am looking for solutions to run my case in GGA for phonon calculations.
Below is my elk.in file.
tasks
0
205
1
210
220
240
245
250
260
ngridq
6 6 6
nxlo
1
ngridk
42 42 42
swidth
0.005
stype
1
maxscl
300
nrmtscf
1.5
ntemp
100
mixtype
3
xctype
(20,0,0)
fxctype
-1
avec
0.5 0.5 0.0
0.5 0.0 0.5
0.0 0.5 0.5
scale
7.6631613998
sppath
'/opt/codes/elk/v8.8.26/species/'
atoms
1 : nspecies
'Al.in' : spfname
1 : natoms; atposl below
0.0 0.0 0.0
plot1d
4 200 : nvp1d, npp1d
0.0 0.0 0.0 : vlvp1d
0.5 0.5 0.0
1.0 0.0 0.0
0.5 0.0 0.0
i have to mention that it dos not have problem with LSDA before i set sctype to (20,0,0)
Hi Farhad,
There are two ways of calculating phonons in Elk. The first is using density functional perturbation theory (DFPT) and the second is with finite differences in a supercell which contains the q-vector. These are tasks 205 and 200, respectively.
Currently, DFPT only works with LDA. The finite differences method will work with most other exchange-correlation functionals available in Elk.
Regards,
Kay.
Hi kay,
thank you for your answer.
where can i read about the exact way these 2 methods(DFPT, SUPERCELL) work to calculate the dynamical matrix?.
Regards,
Farhad