MgO optimum mixing: Difference between revisions
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{{Template:Hybrid_functionals - Tutorial}} | |||
== Task == | |||
Find optimum HSE mixing parameter for MgO. | |||
== Input == | |||
=== {{TAG|POSCAR}} === | |||
<pre> | <pre> | ||
MgO | MgO | ||
| Line 47: | Line 19: | ||
0.50 0.0 0.0 | 0.50 0.0 0.0 | ||
</pre> | </pre> | ||
=== {{TAG|INCAR}} === | |||
############################################## | |||
## Optimum HSE mixing parameter ({{TAGBL|AEXX}}) for MgO | |||
## Expt gap = 7.8 eV | |||
## fit gap wrt. 0<{{TAGBL|AEXX}}<1 | |||
## Compute the bandgap using different value of {{TAGBL|AEXX}} | |||
## in the range (0,1) and find the value which leads | |||
## to the best agreement with the experimental gap. | |||
## hint: the gap grows lineraly with {{TAGBL|AEXX}} | |||
## Better preconverge with PBE first! | |||
############################################## | |||
## Selects the HSE06 hybrid functional | |||
#{{TAGBL|LHFCALC}} = .TRUE. ; {{TAGBL|HFSCREEN}} = 0.2 ; {{TAGBL|AEXX}}=0.25 | |||
#{{TAGBL|ALGO}} = D ; {{TAGBL|TIME}} = 0.4 | |||
## Leave this in | |||
{{TAGBL|ISMEAR}} = 0 | |||
{{TAGBL|SIGMA}} = 0.01 | |||
{{TAGBL|GGA}} = PE | |||
=== {{TAG|KPOINTS}} === | |||
<pre> | |||
k-points | |||
0 | |||
Gamma | |||
4 4 4 | |||
0 0 0 | |||
</pre> | |||
== Calculation == | |||
*script to extract G-eigenvalues and calculate the bandgap | *script to extract G-eigenvalues and calculate the bandgap | ||
| Line 58: | Line 62: | ||
The bandgap is obainted by substracting the eigenvalues written in cband.dat (conduction band | The bandgap is obainted by substracting the eigenvalues written in cband.dat (conduction band | ||
minimum at Gamma) and vband.dat (valence band maximum at Gamma) | minimum at Gamma) and vband.dat (valence band maximum at Gamma) | ||
== Download == | == Download == | ||
[ | [[Media:5 2 MgO mixing.tgz| 5_2_MgO_mixing.tgz]] | ||
{{Template:Hybrid_functionals}} | |||
[[Category:Examples]] | [[Category:Examples]] | ||
Latest revision as of 20:11, 14 March 2022
Overview > bandgap of Si using different DFT+HF methods > MgO optimum mixing > fcc Ni DOS with hybrid functional > Si bandstructure > List of tutorials
Task
Find optimum HSE mixing parameter for MgO.
Input
POSCAR
MgO -18.79350000000000000000 0.5 0.5 0.0 0.0 0.5 0.5 0.5 0.0 0.5 1 1 cart 0.00 0.00 0.00 0.50 0.0 0.0
INCAR
############################################## ## Optimum HSE mixing parameter (AEXX) for MgO ## Expt gap = 7.8 eV ## fit gap wrt. 0<AEXX<1 ## Compute the bandgap using different value of AEXX ## in the range (0,1) and find the value which leads ## to the best agreement with the experimental gap. ## hint: the gap grows lineraly with AEXX ## Better preconverge with PBE first! ############################################## ## Selects the HSE06 hybrid functional #LHFCALC = .TRUE. ; HFSCREEN = 0.2 ; AEXX=0.25 #ALGO = D ; TIME = 0.4 ## Leave this in ISMEAR = 0 SIGMA = 0.01 GGA = PE
KPOINTS
k-points 0 Gamma 4 4 4 0 0 0
Calculation
- script to extract G-eigenvalues and calculate the bandgap
grep " 4 " OUTCAR | head -8 | \
awk 'BEGIN{i=1}{a[i]=$2 ; i=2} END{for (j=1;j<i;j++) print j,a[j]}' > vband.dat
grep " 5 " OUTCAR | head -8 | \
awk 'BEGIN{i=1}{a[i]=$2 ; i=2} END{for (j=1;j<i;j++) print j,a[j]}' > cband.dat
The bandgap is obainted by substracting the eigenvalues written in cband.dat (conduction band minimum at Gamma) and vband.dat (valence band maximum at Gamma)