Electron poor materials research group
Group meeting Dec 2, 2010
Theory- Si bader analysis of
VASP NG(X,Y,Z)F mesh
Procedure
• Static Calculations of the Si FCC structures were computed
– Calculations were done on a Gamma 11X11X11 grid
– Changed NG(X,Y,Z)F to see different values of mesh
– An extra flag was used in the INCAR file: LAECHG = .TRUE.
•
•
•
•
Turns on All Electron CHGCAR file outputs and outputs 3 files
AECCAR0: core charge density
AECCAR1: atomic AE charge density (overlapping atomic charge density)
AECCAR2: AE charge density
• The files AECCAR0 and AECCAR2 are added together for bader
analysis per instructions:
http://theory.cm.utexas.edu/bader/vasp.php
– chgsum.sh AECCAR0 AECCAR2, chsum is a shellscript
• Outputs CHGCAR_sum
• Bader analysis is done on the vasp CHGCAR from the static run
– bader.x -p atom_index -p bader_index CHGCAR -ref CHGCAR_sum
• atom_index: Write the atomic volume index to a charge density file
• bader_index: Write the Bader volume index to a charge density file
Si - Atom location and charge
Bader analysis
ACF.dat for mesh = 500X500X500:
#
X
Y
Z
CHARGE MIN DIST ATOMIC VOL
-------------------------------------------------------------------------------1
0.0000
0.0000
0.0000
4.0000
1.1683 20.4449
2
1.3672
1.3672
1.3672
4.0000
1.1683 20.4449
-------------------------------------------------------------------------------VACUUM CHARGE:
0.0000
VACUUM VOLUME:
0.0000
NUMBER OF ELECTRONS:
8.0000
Bader charge shift = 0.0319
Si - Atom location and charge
Bader analysis
ACF.dat for mesh = 50X50X50
#
X
Y
Z
CHARGE MIN DIST ATOMIC VOL
-------------------------------------------------------------------------------1
0.0000
0.0000
0.0000
4.1278
1.0114 21.0455
2
1.3672
1.3672
1.3672
3.8722
1.0419 19.8443
-------------------------------------------------------------------------------VACUUM CHARGE:
0.0000
VACUUM VOLUME:
0.0000
NUMBER OF ELECTRONS:
8.0000
Bader charge shift = 0.0319
Run STATS
a= 3.867024Å
mesh size
50
60
70
80
90
100
150
200
250
300
350
400
450
500
Grid Size
(a/mesh)
0.07734047
0.064450392
0.055243193
0.048337794
0.042966928
0.038670235
0.025780157
0.019335118
0.015468094
0.012890078
0.011048639
0.009667559
0.008593386
0.007734047
Grid Size
CT
(mesh/a) c-times (electrons)
12.92983959
0.37
0.1278
15.5158075
0.32
0
18.10177542
0.33
0.0319
20.68774334
0.43
-0.0484
23.27371126
0.47
-0.0225
25.85967917
0.65
0
38.78951876
1.5
0.0044
51.71935835
3.1
-0.0184
64.64919794
5.95
-0.0033
77.57903752
9.93
0
90.50887711 16.33
0.0027
103.4387167 24.58
-0.0089
116.3685563 36.85
0.0022
129.2983959 101.53
0
|CT|
(electrons)
0.1278
0
0.0319
0.0484
0.0225
0
0.0044
0.0184
0.0033
0
0.0027
0.0089
0.0022
0
Charge Transfer
0.14
Electron Charge Transfer
0.12
Charge Transfer
0.1
0.08
0.06
0.04
0.02
0
50
60
70
80
90
100
150
200
Grid Size
250
300
350
400
450
500
Run Time
40
Time of runs per mesh size
35
30
25
y = 0.0954e0.4449x
R² = 0.9399
20
15
10
5
0
50
60
70
80
90
100
150
200
250
300
mesh size
black line = exponential curve fit
350
400
450