VASP calculation of fcc Si bandstructure

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

Let’s draw band structure.

INCAR、POSCAR、POTCAR are the same as those of “fcc Si” or “fcc Si DOS“. CHGCAR of “fcc Si DOS” is used here. 

KPOINTS

k-points for bandstructure L-G-X-U K-G
 10
line
reciprocal
  0.50000  0.50000  0.50000    1
  0.00000  0.00000  0.00000    1

  0.00000  0.00000  0.00000    1
  0.00000  0.50000  0.50000    1

  0.00000  0.50000  0.50000    1
  0.25000  0.62500  0.62500    1

  0.37500  0.7500   0.37500    1
  0.00000  0.00000  0.00000    1

KPOINTS is different from previous ones.

line 3: To generate strings of k-points connecting specific points of the Brillouin zone, the third line of the KPOINTS file must start with an L for line-mode.
line 4: how to describe coordinate
line 5-: coordinate and weight

You can survay specific points of the Brillouin zone using KVEC in bilbao crystallographic server with the space group. The space group of fcc is Fm-3m (225).

Coordinates are summarized in the table and you can choose what you want. 

To make band structure figure, we should calculate with ICHARG=1 before (like fcc Si DOS). And then, we can calculate with ICHARG=11. 

Results

The easiest way to draw band structure would be using p4vasp. However, I could not compile p4vasp on Mac… If you use p4vasp, open vasprun.xml and select “DOS+bands”→”Show”→”Bands”. You can output with “Graph”→”Export”.

I’m not sure but we can draw band structure with EIGENVAL.

EIGENVAL

    1    1    1    1
  0.1482975E+02  0.2757716E-09  0.2757716E-09  0.2757716E-09  0.5000000E-15
  1.000000000000000E-004
  CAR 
 fcc Si                                  
      4     40      6
 
  0.5000000E+00  0.5000000E+00  0.5000000E+00  0.2500000E-01
    1        2.313016   1.000000
    2        3.056922   1.000000
    3       18.189508   0.000000
    4       18.189509   0.000000
    5       20.733882   0.000000
    6       20.733883   0.000000
    ・
    ・
    ・

line 1: “number of atom” “number of atom” “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: NELECT? k-points NBANDS?
line 8: coordinate of k-points weight
line 9-: band energy??

I think we can draw the same figure with band energy and distance from k-points in EIGENVAL, Of course, we can use vasprun.xml.

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