Si bandstructure: Difference between revisions

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Line 26: Line 26:
  System = fcc Si  
  System = fcc Si  
  ISMEAR = 0; SIGMA = 0.1;
  ISMEAR = 0; SIGMA = 0.1;
LORBIT=11


*KPOINTS
*KPOINTS
*KPOINTS
<pre>
<pre>
Line 69: Line 67:
P4VASP: [http://www.p4vasp.at p4v]
P4VASP: [http://www.p4vasp.at p4v]


== 0-weight (Fake) SC procedure ==
== 0-weight (Fake) SC procedure (PBE & Hybrids) ==


This procedure can be applied tocompute bandstructure at Hybrid functionals level.
=== Standard DFT run ===
*INCAR
*INCAR
<pre>
<pre>
## Do a HSE hybrid functional banstructure calculation with
## (1) the KPOINTS.HSE.G-X file
##    (i)  preconverge with DFT using the standard KPOINTS file
##    (ii)  HSE calculation using the KPOINTS.HSE.G-X file
##    (iii) plot with p4vasp
## (2) using VASP2WANNIER90 (Use the standard KPOINTS file)
##    (i)  preconverge with DFT
##    (ii)  HSE calculation with  LWANNIER90=.TRUE. and wannier.win
##    (iii) Run wannier90: wannier90.x wannier90
##    (iv)  Restart wannier90 wih the bandplot options in wannier.win uncommented
## Better first preconverge with DFT
## Default       
## Default       
ISMEAR =  0
ISMEAR =  0
Line 105: Line 94:
  4 4 4
  4 4 4
  0 0 0
  0 0 0
</pre>
=== Hybrid calculation using a uistably modified KPOINTS file ===
*INCAR
<pre>
## Default     
ISMEAR =  0
SIGMA  =  0.01
GGA    = PE
## HSE
LHFCALC = .TRUE. ; HFSCREEN = 0.2 ; AEXX = 0.25
ALGO = D ; TIME = 0.4 ; LDIAG = .TRUE.
</pre>
</pre>


Line 133: Line 136:
</pre>
</pre>


*POSCAR
=== VASP2WANNIER90 ===
<pre>
system Si
5.430
0.5 0.5 0.0
0.0 0.5 0.5
0.5 0.0 0.5
2
cart
0.00 0.00 0.00
0.25 0.25 0.25
</pre>


*wannier90.win
*wannier90.win

Revision as of 15:39, 9 June 2012

Description: Bandstructure for Si within DFT+HF

Mind: For PBE bandstructure refer to Fcc Si bandstructure example.

Bandstructure in VASP can be obtained in three different ways:

Standard procedure (DFT)

Only possible within DFT. Described in Fcc Si bandstructure example:

Standard self-consistent (SC) run

  • POSCAR
system Si
5.430
0.5 0.5 0.0
0.0 0.5 0.5
0.5 0.0 0.5
2
cart
0.00 0.00 0.00
0.25 0.25 0.25
  • INCAR
System = fcc Si 
ISMEAR = 0; SIGMA = 0.1;
  • KPOINTS
4x4x4
 0
G
 4 4 4
 0 0 0

Non-SC calculation (ICHARG=11)

Use preconverged CHGCAR file and a suitable KPOINTS file (KPOINTS_PBE_bands)

  • INCAR
System = fcc Si 
ICHARG=11 #charge read file
ISMEAR = 0; SIGMA = 0.1;
LORBIT=11
  • 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

Plot using p4v

P4VASP: p4v

0-weight (Fake) SC procedure (PBE & Hybrids)

This procedure can be applied tocompute bandstructure at Hybrid functionals level.

Standard DFT run

  • INCAR
## Default       
ISMEAR =  0
SIGMA  =  0.01
GGA    = PE

## HSE
#LHFCALC = .TRUE. ; HFSCREEN = 0.2 ; AEXX = 0.25
#ALGO = D ; TIME = 0.4 ; LDIAG = .TRUE.

##VASP2WANNIER
#LWANNIER90=.TRUE.
  • KPOINTS
Automatically generated mesh
 0
G
 4 4 4
 0 0 0

Hybrid calculation using a uistably modified KPOINTS file

  • INCAR
## Default       
ISMEAR =  0
SIGMA  =  0.01
GGA    = PE

## HSE
LHFCALC = .TRUE. ; HFSCREEN = 0.2 ; AEXX = 0.25
ALGO = D ; TIME = 0.4 ; LDIAG = .TRUE.
  • KPOINTS_HSE_bands
Explicit k-points list
      18
Reciprocal lattice
    0.00000000000000    0.00000000000000    0.00000000000000             1
    0.25000000000000    0.00000000000000    0.00000000000000             8
    0.50000000000000    0.00000000000000    0.00000000000000             4
    0.25000000000000    0.25000000000000    0.00000000000000             6
    0.50000000000000    0.25000000000000    0.00000000000000            24
   -0.25000000000000    0.25000000000000    0.00000000000000            12
    0.50000000000000    0.50000000000000    0.00000000000000             3
   -0.25000000000000    0.50000000000000    0.25000000000000             6
0.00000000 0.00000000 0.00000000 0.000
0.00000000 0.05555556 0.05555556 0.000
0.00000000 0.11111111 0.11111111 0.000
0.00000000 0.16666667 0.16666667 0.000
0.00000000 0.22222222 0.22222222 0.000
0.00000000 0.27777778 0.27777778 0.000
0.00000000 0.33333333 0.33333333 0.000
0.00000000 0.38888889 0.38888889 0.000
0.00000000 0.44444444 0.44444444 0.000
0.00000000 0.50000000 0.50000000 0.000

VASP2WANNIER90

  • wannier90.win
num_wann=8
num_bands=8

Begin Projections
Si:sp3
End Projections

dis_froz_max=9
dis_num_iter=1000

guiding_centres=true

#restart         =  plot
#bands_plot      =  true
#begin kpoint_path
#L 0.50000  0.50000 0.5000 G 0.00000  0.00000 0.0000
#G 0.00000  0.00000 0.0000 X 0.50000  0.00000 0.5000
#X 0.50000  0.00000 0.5000 K 0.37500 -0.37500 0.0000
#K 0.37500 -0.37500 0.0000 G 0.00000  0.00000 0.0000
#end kpoint_path
#bands_num_points 40
#bands_plot_format gnuplot xmgrace

begin unit_cell_cart
     2.7150000     2.7150000     0.0000000
     0.0000000     2.7150000     2.7150000
     2.7150000     0.0000000     2.7150000
end unit_cell_cart

begin atoms_cart
Si       0.0000000     0.0000000     0.0000000
Si       1.3575000     1.3575000     1.3575000
end atoms_cart

mp_grid =     4     4     4

begin kpoints
     0.0000000     0.0000000     0.0000000
     0.2500000     0.0000000     0.0000000
     0.5000000     0.0000000     0.0000000
     0.2500000     0.2500000     0.0000000
     0.5000000     0.2500000     0.0000000
    -0.2500000     0.2500000     0.0000000
     0.5000000     0.5000000     0.0000000
    -0.2500000     0.5000000     0.2500000
     0.0000000     0.2500000     0.0000000
     0.0000000     0.0000000     0.2500000
    -0.2500000    -0.2500000    -0.2500000
    -0.2500000     0.0000000     0.0000000
     0.0000000    -0.2500000     0.0000000
     0.0000000     0.0000000    -0.2500000
     0.2500000     0.2500000     0.2500000
     0.0000000     0.5000000     0.0000000
     0.0000000     0.0000000     0.5000000
    -0.5000000    -0.5000000    -0.5000000
     0.0000000     0.2500000     0.2500000
     0.2500000     0.0000000     0.2500000
    -0.2500000    -0.2500000     0.0000000
    -0.2500000     0.0000000    -0.2500000
     0.0000000    -0.2500000    -0.2500000
     0.0000000     0.5000000     0.2500000
     0.2500000     0.0000000     0.5000000
    -0.2500000    -0.2500000     0.2500000
    -0.5000000    -0.2500000    -0.5000000
     0.2500000     0.5000000     0.0000000
     0.2500000    -0.2500000    -0.2500000
    -0.5000000    -0.5000000    -0.2500000
     0.0000000     0.2500000     0.5000000
    -0.2500000     0.2500000    -0.2500000
    -0.2500000    -0.5000000    -0.5000000
     0.5000000     0.0000000     0.2500000
    -0.5000000    -0.2500000     0.0000000
     0.0000000    -0.5000000    -0.2500000
    -0.2500000     0.0000000    -0.5000000
     0.2500000     0.2500000    -0.2500000
     0.5000000     0.2500000     0.5000000
    -0.2500000    -0.5000000     0.0000000
    -0.2500000     0.2500000     0.2500000
     0.5000000     0.5000000     0.2500000
     0.0000000    -0.2500000    -0.5000000
     0.2500000    -0.2500000     0.2500000
     0.2500000     0.5000000     0.5000000
    -0.5000000     0.0000000    -0.2500000
     0.0000000    -0.2500000     0.2500000
     0.2500000     0.0000000    -0.2500000
    -0.2500000    -0.2500000    -0.5000000
     0.2500000     0.5000000     0.2500000
     0.2500000    -0.2500000     0.0000000
    -0.5000000    -0.2500000    -0.2500000
     0.2500000     0.2500000     0.5000000
     0.0000000     0.2500000    -0.2500000
    -0.2500000    -0.5000000    -0.2500000
     0.5000000     0.2500000     0.2500000
    -0.2500000     0.0000000     0.2500000
     0.0000000     0.5000000     0.5000000
     0.5000000     0.0000000     0.5000000
     0.2500000    -0.2500000     0.5000000
     0.5000000     0.2500000    -0.2500000
    -0.5000000    -0.2500000    -0.7500000
     0.2500000    -0.5000000    -0.2500000
    -0.2500000     0.2500000    -0.5000000
end kpoints
  • README.txt
Bandstructure plot in VASP (Three different ways)

1) Standard way: PBE (Fcc Si bandstructure example).
   1.1  Standard self-consistent (SC) run
   1.2  non-SC calculation (ICHARG=11) using preconverged CHGCAR file and KPOINTS_PBE_bands
   1.3  Plot using p4v

2) Fake SC procedure: PBE & HSE
   2.1 Standard self-consistent (SC) run
   2.2 Additional SC-run using KPOINTS_HSE_bands
   2.3 Plot using p4v 

----
The file KPOINTS_HSE_bands is constructed by copying the IBZKPT file from run 2.1 to the KPOINTS file:

IBZKPT
Automatically generated mesh
       8
Reciprocal lattice
    0.00000000000000    0.00000000000000    0.00000000000000             1
    0.25000000000000    0.00000000000000    0.00000000000000             8
    0.50000000000000    0.00000000000000    0.00000000000000             4
    0.25000000000000    0.25000000000000    0.00000000000000             6
    0.50000000000000    0.25000000000000    0.00000000000000            24
   -0.25000000000000    0.25000000000000    0.00000000000000            12
    0.50000000000000    0.50000000000000    0.00000000000000             3
   -0.25000000000000    0.50000000000000    0.25000000000000             6

Then add the desired additional k-points with zero weight and change the total number of k-points

Explicit k-points list
      18 <--- CHANGE TOTAL NUMBER OF K-POINTS !!
Reciprocal lattice
    0.00000000000000    0.00000000000000    0.00000000000000             1
    0.25000000000000    0.00000000000000    0.00000000000000             8
    0.50000000000000    0.00000000000000    0.00000000000000             4
    0.25000000000000    0.25000000000000    0.00000000000000             6
    0.50000000000000    0.25000000000000    0.00000000000000            24
   -0.25000000000000    0.25000000000000    0.00000000000000            12
    0.50000000000000    0.50000000000000    0.00000000000000             3
   -0.25000000000000    0.50000000000000    0.25000000000000             6
0.00000000 0.00000000 0.00000000 0.000 <--- ZERO WEIGHT !!
0.00000000 0.05555556 0.05555556 0.000
0.00000000 0.11111111 0.11111111 0.000
0.00000000 0.16666667 0.16666667 0.000
0.00000000 0.22222222 0.22222222 0.000
0.00000000 0.27777778 0.27777778 0.000
0.00000000 0.33333333 0.33333333 0.000
0.00000000 0.38888889 0.38888889 0.000
0.00000000 0.44444444 0.44444444 0.000
0.00000000 0.50000000 0.50000000 0.000
----

3) VASP2WANNIER90: PBE, HSE & GW 
   3.1 Standard SC run using the existing wannier.win file  
   3.2 run wannier90 (wannier90.x wannier90) to generate MLWFs
   3.3 uncomment bandstructure plot flags in wannier90.win and restart wannier90

----
If the wannier90.win file does not exist VASP will create a default wannier90.win compatible with
the POSCAR and INCAR, which need to be suitably modify by including the proper instruction required 
to generate the MLWFs (refer to the wannier90 manual):

default wannier90.win
 num_wann =     8  ! set to NBANDS by VASP

use_bloch_phases = .T.

begin unit_cell_cart
     2.7150000     2.7150000     0.0000000
     0.0000000     2.7150000     2.7150000
     2.7150000     0.0000000     2.7150000
end unit_cell_cart

begin atoms_cart
Si       0.0000000     0.0000000     0.0000000
Si       1.3575000     1.3575000     1.3575000
end atoms_cart

mp_grid =     4     4     4

begin kpoints
     0.0000000     0.0000000     0.0000000
     0.2500000     0.0000000     0.0000000
     0.5000000     0.0000000     0.0000000
     0.2500000     0.2500000     0.0000000
     0.5000000     0.2500000     0.0000000
    -0.2500000     0.2500000     0.0000000
     0.5000000     0.5000000     0.0000000
    -0.2500000     0.5000000     0.2500000
     0.0000000     0.2500000     0.0000000
     0.0000000     0.0000000     0.2500000
    -0.2500000    -0.2500000    -0.2500000
    -0.2500000     0.0000000     0.0000000
     0.0000000    -0.2500000     0.0000000
     0.0000000     0.0000000    -0.2500000
     0.2500000     0.2500000     0.2500000
     0.0000000     0.5000000     0.0000000
     0.0000000     0.0000000     0.5000000
    -0.5000000    -0.5000000    -0.5000000
     0.0000000     0.2500000     0.2500000
     0.2500000     0.0000000     0.2500000
    -0.2500000    -0.2500000     0.0000000
    -0.2500000     0.0000000    -0.2500000
     0.0000000    -0.2500000    -0.2500000
     0.0000000     0.5000000     0.2500000
     0.2500000     0.0000000     0.5000000
    -0.2500000    -0.2500000     0.2500000
    -0.5000000    -0.2500000    -0.5000000
     0.2500000     0.5000000     0.0000000
     0.2500000    -0.2500000    -0.2500000
    -0.5000000    -0.5000000    -0.2500000
     0.0000000     0.2500000     0.5000000
    -0.2500000     0.2500000    -0.2500000
    -0.2500000    -0.5000000    -0.5000000
     0.5000000     0.0000000     0.2500000
    -0.5000000    -0.2500000     0.0000000
     0.0000000    -0.5000000    -0.2500000
    -0.2500000     0.0000000    -0.5000000
     0.2500000     0.2500000    -0.2500000
     0.5000000     0.2500000     0.5000000
    -0.2500000    -0.5000000     0.0000000
    -0.2500000     0.2500000     0.2500000
     0.5000000     0.5000000     0.2500000
     0.0000000    -0.2500000    -0.5000000
     0.2500000    -0.2500000     0.2500000
     0.2500000     0.5000000     0.5000000
    -0.5000000     0.0000000    -0.2500000
     0.0000000    -0.2500000     0.2500000
     0.2500000     0.0000000    -0.2500000
    -0.2500000    -0.2500000    -0.5000000
     0.2500000     0.5000000     0.2500000
     0.2500000    -0.2500000     0.0000000
    -0.5000000    -0.2500000    -0.2500000
     0.2500000     0.2500000     0.5000000
     0.0000000     0.2500000    -0.2500000
    -0.2500000    -0.5000000    -0.2500000
     0.5000000     0.2500000     0.2500000
    -0.2500000     0.0000000     0.2500000
     0.0000000     0.5000000     0.5000000
     0.5000000     0.0000000     0.5000000
     0.2500000    -0.2500000     0.5000000
     0.5000000     0.2500000    -0.2500000
    -0.5000000    -0.2500000    -0.7500000
     0.2500000    -0.5000000    -0.2500000
    -0.2500000     0.2500000    -0.5000000
end kpoints
----

Wannier90 Manual: WANNIER90 manual

LWANNIER90 in the VASP Manual: LWANNIER90.

Download

5_4_Si_bandstructure.tgz

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