Fcc Si DOS: Difference between revisions

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**Increase the number of k points for the DOS and set {{TAG|ICHARG}}=11 (charge density from the last self-consistent run). {{TAG|ICHARG}}=11 treats each k point independently and keeps the charge density and the potential fixed.
**Increase the number of k points for the DOS and set {{TAG|ICHARG}}=11 (charge density from the last self-consistent run). {{TAG|ICHARG}}=11 treats each k point independently and keeps the charge density and the potential fixed.


*Read {{TAG|CHGCAR}} from previous run. To copy the self-consistent charge density of example {{TAG|fccSi}} to your current working
*Read {{TAG|CHGCAR}} from previous run. To copy the self-consistent charge density of example {{TAG|fcc_Si}} to your current working
directory (assumed to be fccSidos), type: $ cp ../fccSi/CHGCAR .
directory (assumed to be fccSidos), type: $ cp ../fccSi/CHGCAR .



Revision as of 14:42, 8 May 2017

Task

Calculation of the DOS in fcc Si.

Input

POSCAR

fcc Si:
 3.9
 0.5 0.5 0.0
 0.0 0.5 0.5
 0.5 0.0 0.5
   1
cartesian
0 0 0

INCAR

System = fcc Si 
# ICHARG = 11 #charge read file
ENCUT  =    240
ISMEAR = -5 #tetrahedron
LORBIT = 11

KPOINTS

k-points
 0
Monkhorst Pack
 21 21 21
 0  0  0


Calculation

  • Perform a static (NSW=0, IBRION=-1) self consistent calculation for the DOS (the DOS is found in the DOSCAR file.
  • For large systems:
    • Converge with a small number of k points.
    • Increase the number of k points for the DOS and set ICHARG=11 (charge density from the last self-consistent run). ICHARG=11 treats each k point independently and keeps the charge density and the potential fixed.
  • Read CHGCAR from previous run. To copy the self-consistent charge density of example fcc_Si to your current working

directory (assumed to be fccSidos), type: $ cp ../fccSi/CHGCAR .

  • The bash-script plotdos invokes awk and gnuplot to get the DOS from the vasprun.xml file and plot it.
awk 'BEGIN{i=1} /dos>/,\
                /\/dos>/ \
                 {a[i]=$2 ; b[i]=$3 ; i=i+1} \
     END{for (j=12;j<i-5;j++) print a[j],b[j]}' vasprun.xml > dos.dat

ef=`awk '/efermi/ {print $3}' vasprun.xml`

cat >plotfile<<!
# set term postscript enhanced eps colour lw 2 "Helvetica" 20
# set output "optics.eps"
plot "dos.dat" using (\$1-$ef):(\$2) w lp
! 

gnuplot -persist plotfile

rm dos.dat plotfile

Download

fccSidos.tgz


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