Dielectric properties of Si: Difference between revisions

Revision as of 15:46, 16 March 2017

Description: the static and frequency dependent dielectric properties of Si.

Please have a look at the example on calculation of the static and frequency dependent dielectric properties of SiC first. The same procedures apply to this example.

INCAR file for the static calculation

## Static dielectric properties by means of DFPT
#NBANDS = 4
#EDIFF = 1E-6
#LEPSILON = .TRUE.
## try to add this to the DFPT calculation
#LPEAD = .TRUE.
## to get the ionic contributions to the
## static dielectric properties from
## perturbation theory
#IBRION = 8
        
## Static dielectric properties by means of PEAD
#EDIFF = 1E-8      # finite field requires very tight convergence
#LCALCEPS = .TRUE.
#NELM = 100
        
## Leave this in
ISMEAR = 0
SIGMA = 0.01
GGA = PE

INCAR for the frequency dependent calculation

## Frequency dependent dielectric tensor without
## local field effects
#ALGO = Exact
#NBANDS  = 64
#LOPTICS = .TRUE. ; CSHIFT = 0.1
#NEDOS = 2000
## and you might try with the following
#LPEAD = .TRUE.
    
## Frequency dependent dielectric tensor with and
## without local field effects in RPA and due to
## changes in the DFT xc-potential
## N.B.: beware one first has to have done a
## calculation with LOPTICS = .TRUE. (see above)
#ALGO = CHI ; LSPECTRAL = .FALSE.
#LRPA = .FALSE.
## be sure to take the same number of bands as for
## the LOPTICS = .TRUE. calculation, otherwise the
## WAVEDER file is not read correctly
# NBANDS = 64
    
## Leave this in
ISMEAR = 0
{{TAGBL|SIGMA} = 0.01
GGA = PE

POSCAR

system Si
5.430
0.5 0.5 0.0
0.0 0.5 0.5
0.5 0.0 0.5
2
cart
0.00 0.00 0.00
0.25 0.25 0.25

Used INCAR Tags

ALGO, CSHIFT, EDIFF, GGA, IBRION, ISMEAR, LCALCEPS, LEPSILON, LOPTICS, LPEAD, LRPA, NBANDS, NEDOS, NELM, SIGMA

Download

Si_dielectric.tgz

To the list of examples or to the main page

@@ Line 4: / Line 4: @@
 Please have a look at the example on [[Dielectric_properties_of_SiC|calculation of the static and frequency dependent dielectric properties of SiC]] first.
 The same procedures apply to this example.
+*{{TAG|INCAR}} file for the static calculation
+ ## Static dielectric properties by means of DFPT
+ #{{TAGBL|NBANDS}} = 4
+ #{{TAGBL|EDIFF}} = 1E-6
+ #{{TAGBL|LEPSILON}} = .TRUE.
+ ## try to add this to the DFPT calculation
+ #{{TAGBL|LPEAD}} = .TRUE.
+ ## to get the ionic contributions to the
+ ## static dielectric properties from
+ ## perturbation theory
+ #{{TAGBL|IBRION}} = 8
+ ## Static dielectric properties by means of PEAD
+ #{{TAGBL|EDIFF}} = 1E-8      # finite field requires very tight convergence
+ #{{TAGBL|LCALCEPS}} = .TRUE.
+ #{{TAGBL|NELM}} = 100
+ ## Leave this in
+ {{TAGBL|ISMEAR}} = 0
+ {{TAGBL|SIGMA}} = 0.01
+ {{TAGBL|GGA}} = PE
+*{{TAG|INCAR}} for the frequency dependent calculation
+ ## Frequency dependent dielectric tensor without
+ ## local field effects
+ #{{TAGBL|ALGO}} = Exact
+ #{{TAGBL|NBANDS}}  = 64
+ #{{TAGBL|LOPTICS}} = .TRUE. ; {{TAGBL|CSHIFT}} = 0.1
+ #{{TAGBL|NEDOS}} = 2000
+ ## and you might try with the following
+ #{{TAGBL|LPEAD}} = .TRUE.
+ ## Frequency dependent dielectric tensor with and
+ ## without local field effects in RPA and due to
+ ## changes in the DFT xc-potential
+ ## N.B.: beware one first has to have done a
+ ## calculation with {{TAGBL|LOPTICS}} = .TRUE. (see above)
+ #{{TAGBL|ALGO}} = CHI ; {{TAGBL|LSPECTRAL}} = .FALSE.
+ #{{TAGBL|LRPA}} = .FALSE.
+ ## be sure to take the same number of bands as for
+ ## the {{TAGBL|LOPTICS}} = .TRUE. calculation, otherwise the
+ ## {{TAGBL|WAVEDER}} file is not read correctly
+ # {{TAGBL|NBANDS}} = 64
+ ## Leave this in
+ {{TAGBL|ISMEAR}} = 0
+ {{TAGBL|SIGMA} = 0.01
+ {{TAGBL|GGA}} = PE
+*{{TAG|POSCAR}}
+ system Si
+.430
+.5 0.5 0.0
+.0 0.5 0.5
+.5 0.0 0.5
+ cart
+.00 0.00 0.00
+.25 0.25 0.25
 == Used INCAR Tags ==