VASP Calculation for Density of States (fcc Si DOS)

Series of try VASP sample. “fcc Si DOS” here.

http://cms.mpi.univie.ac.at/wiki/index.php/VASP_workshop_2003
http://cms.mpi.univie.ac.at/wiki/index.php/Fcc_Si_DOS

DOS means Density of States.

INCAR

general:
 System = fcc Si   # names of System
 ICHARG = 11       # charge read file
 ENCUT  = 240      # energy cutoff in eV
 ISMEAR = -5       # tetrahedron
 LORBIT = 11       # about RWIGS, PROCAR, PROOUT

line 1: comment? please teach me, someone. 
ICHARG: how VASP constructs the initial charge density. 

if we want to calculate partial DOS, 10 is added to ICHARG from the original value. So, ICHARG is 10, 11, or 12. After just one self consistent loop,  set this value for the shortening calculation time of precise k-points to draw partial DOS.

はじめてのVASP原理から使用法、適用例まで 西谷滋人

ISMEAR: 

For the calculation of the total energy in bulk materials we recommend the tetrahedron method with Blöchl corrections (ISMEAR=-5). This method also gives a good account for the electronic density of states (DOS).  

VASP Wiki (https://cms.mpi.univie.ac.at/wiki/index.php/ISMEAR)

LORBIT: setting for RWIGS in INCAR and output files PROCAR, PROOUT. Values is explained in Vaspwiki.

Before setting ICHARG=11, run vasp without ICHARG. Then run vasp again with ICHARG=11 and CHGCAR file.

Both partial DOS and projected DOS is written as PDOS, and they are the same.

Results

DOSCAR

The result of DOS is saved in DOSCAR. Unit is [number of states / unit cell].

   1   1   1   0
  0.1482975E+02  0.2757716E-09  0.2757716E-09  0.2757716E-09  0.5000000E-15
  1.000000000000000E-004
  CAR 
 fcc Si                                  
     29.34297713     -6.37833197  301      9.89512679      1.00000000
     -6.378  0.0000E+00  0.0000E+00
     -6.259  0.0000E+00  0.0000E+00
     -6.140  0.0000E+00  0.0000E+00
        ・
        ・
        ・
    29.34297713     -6.37833197  301      9.89512679      1.00000000
     -6.378  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00
     -6.259  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00
     -6.140  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00  0.0000E+00
        ・
        ・
        ・

line 1: number of atoms, number of atoms, number of loops, ISPIN (1:non-spin, 2: spin)
line 2: Volume(Å3), lattice parameter(m),    ??
line 3: ??
line 4: ??
line 5: System value in INCAR?
line 6: EMax[eV] EMin[eV] NEDOS EF[eV] spin(1:non-spin, 2: spin)
line 7-:
<if spin is not calculate,>
energy DOS integrated DOS
line 13-:
If LORBIT=11 is set, PDOS is output. line 13 is the same as line 6.
As for line 14-, spin is not considered and, 
energy s-DOS p-DOS d-DOS
10 column means (I guess)
energy s py px pz dxy dyz dz2-r2 dxz dx2-y2

For relaxations, the DOSCAR is usually useless. If you want to get an accurate DOS for the final configuration, first copy CONTCAR to POSCAR and continue with one static (ISTART=1; NSW=0) calculation.

Vasp Wiki (https://cms.mpi.univie.ac.at/wiki/index.php/DOSCAR)

The script, which makes plot with vasprun.xml using gnuplot, is shown in the sample page. We can make figure using Excel or other plotting software. You can use p4vasp.

The result is shown in the following figure. 

Sum of PDOS does not equal to total DOS? I don’t know but PDOS depends on Wigner-Seitz radius. (Total DOS is not changed.)

I don’t understand DOS, but FCC Si is metal because DOS is not 0 on the Fermi level.

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