Fcc Si DOS
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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:
- 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 . You must do this otherwise VASP can not read the CHGCAR and will terminate.
- The smearing of the k points is set to the tetrahedron method with Blöchl corrections (ISMEAR=-5 to fi the problem
- To plot the DOS use p4vasp:
- Alternatively the bash-script plotdos.sh 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