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--- band_structure [2009/11/25 22:24]
jelen
+++ band_structure [2012/11/30 10:16]
dani
@@ Line 55: / Line 55: @@
   multiplot> plot "ek.dat" using 1:7 with lines
-{{:si-bulk:si-bulk.png|Si-bulk Band Structure}}
+{{:si-bulk:si-bulk.png?400|Si-bulk Band Structure}}
 ===== DOS =====
+To plot Density of state, first, we have to achieve SCF solution in the same way as above (see previous [[band_structure|section]]).
+Next we perform calculation with fixed SCF charges (switching on **''ifixcharge =1''**). The DOS calculation is initialized via variable **''iwrtdos''** in the section **''&OUTPUT''**. Hence, our **''fireball.in''** file looks like that:
+  &OPTION
+  basisfile = Si.bas
+  lvsfile = Si.lvs
+  kptpreference = Si.kpts
+  nstepf = 1
+  ifixcharge = 1
+  rescal = 5.5
+  &END
+  &OUTPUT
+  iwrtdos = 1
+  &END
+In addition, **''dos.optional''** has to be presented in a working directory having following distance:
+.0                   ! scale factor (leave 1.0)
+        2            ! list of atoms to analyze DOS
+                   ! number of energy steps
+  -18.0   0.05          ! initial energy, energy step
+                     ! leave untouched
+.0     0.0           ! leave untouched
+.05                  ! imaginary part of Green function (controls energy level smearing)
+After finishing a run, we obtain **''dens_001.dat''**,**''dens_002.dat''** including projected DOS on two Si atoms in the unit cell (including projected DOS onto individual shells of atoms). Additionally, there is a file **''dens_TOT.dat''** containing DOS. Here, a first column means energy and a second one DOS.
+  mac135> gnuplot
+  gnuplot> set xrange [0:1]
+  gnuplot> set yrange [-17:0]
+  gnuplot> set xlabel "DOS [arb. units]"
+  gnuplot> set ylabel "Energy [eV]"
+  gnuplot>  plot "dens_TOT.dat" using 2:1 title 'Total DOS' with lines, \
+            "dens_001.dat" using 11:1 title 'PDOS Si atom ' with lines
+{{:si-bulk:pdos-si_bulk.png?400|DOS Si Bulk}}
+===== The bulk modulus =====
+  $ ls
+  Fdata  uno.bas  uno.kpts  uno.lvs  vol.sh
+  $ head uno.bas
+      0.000000      0.000000      0.000000
+      0.250000      0.250000      0.250000
+  $ head uno.kpts
+
+  -2.35619449         -2.35619449         -2.35619449        0.03125000
+  -3.92699081         -0.78539816         -0.78539816        0.03125000
+  -5.49778713          0.78539816          0.78539816        0.03125000
+  -7.06858347          2.35619449          2.35619449        0.03125000
+  -0.78539816         -3.92699081         -0.78539816        0.03125000
+  -2.35619449         -2.35619449          0.78539816        0.03125000
+  -3.92699081         -0.78539816          2.35619449        0.03125000
+  -5.49778713          0.78539816          3.92699081        0.03125000
+.78539816         -5.49778713          0.78539816        0.03125000
+  $ head  uno.lvs
+.5000    0.5000    0.0000
+.5000    0.0000    0.5000
+.0000    0.5000    0.5000
+The script to calculate the bulk modulus
+  $ cat vol.sh
+  #!/bin/bash
+  ##----- Parametros de control (el parametro de red tiene que encontrase entre ini fin  --------##
+  N=10
+  ini=5.0
+  fin=6.0
+  ##----------Funcion analisis para dos atomos/celda-----------------------------------------##
+  function analisis {
+  ETOT=$(grep 'ETOT' salida.out|cut -d'=' -f2)
+  sigma=$(grep sigma salida.out | cut -d'=' -f16 | tail -1)
+  charge=$(head -2 uno.bas | tail -1 | tr -s ' ' | cut -d' ' -f2)' -> '$(head -2 CHARGES | tail -1)
+  charge=$charge' ;'$(head -3 uno.bas | tail -1 | tr -s ' ' | cut -d' ' -f2)' -> '
+  charge=$charge$(tail -1 CHARGES)
+  echo $rescal$'\t'$ETOT$'\t'$sigma$'\t'$charge$'\t'>>salida
+  }
+  ##------------------------------------------------------------------------------------------##
+  function start {
+  rm -fr salida
+  for((i=0;i<=N;i++))
+  do
+  rescal=$(python -c "print '%.6f' % ($i*1.0*($fin-$ini)/$N+$ini)")
+  echo "&option
+  basisfile = uno.bas
+  lvsfile = uno.lvs
+  kptpreference = uno.kpts
+  rescal = $rescal
+  sigmatol = 0.000001
+  nstepf = 1
+  &end
+  &output
+  iwrtxyz = 1
+  &end" > fireball.in
+  ../progs/fireball.x > salida.out
+  analisis
+  done
+  }
+  ##----------------------------------1º start  ----------------------------------------------##
+  start
+  ##-----------------------------buscamos el minimo ------------------------------------------##
+  min=$(python -c "
+  x0 = []
+  y0 = []
+  for line in file(\"salida\"):
+     line = line.split()
+     x = line[0]
+     y = line[1]
+     x0.append(x)
+     y0.append(y)
+  j=0
+  for i in range(len(x0)):
+    if y0[j]< y0[i]:
+      j=i
+  print x0[j]")
+  cp salida borrar
+  rm -fr aux.py
+  ##----------------------------------2º start -----------------------------------------------##
+  N=40
+  d=0.4
+  ini=$(python -c "print '%.6f' % (1.0*($min-$d))")
+  fin=$(python -c "print '%.6f' % (1.0*($min+$d))")
+  start
+  mv salida Vol.dat
+  ##------------------------------------------------------------------------------------------##
+In the 1º start of the script "vol.sh" takes 10 points between 5-6:
+{{:bulk-si-10.png|}}
+In the 2º start of the script "vol.sh" takes 40 points between the minimum of the 1º start
+{{:si-bulk-40.png|}}
+The scripts uses the parameter rescal in fireball.in and unitary positions and lattice vectors with 2 atoms/cell
+to obtain the kpts points we used xeo:
+{{:xeo-menu-kpts.png|}}
+{{:xeo-kpts.png|}}
+The bulk mudulus can be calculed also with xeo (Utilities->Bulk modulus), in the in line command:
+  $ xeo -Bulk Vol.dat zincblende
+  E_min =     -214.35239    eV
+  a_min =        5.43719    angs
+  Volumen =       40.18518 ang**3
+  Bulk modulus =      100.79399  GPa

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