[Pw_forum] band structure of Si unit cell and supercer
Muthu V
muthu.physicsmath at gmail.com
Wed Jan 22 19:13:51 CET 2014
Dear QE users
i have run band structure calculation for Si unit cell and 2x2x2
super-cell. as far as i know the both band structure should be same since
2x2x2 super-cell is = simply repeating unit cell in space twice all
direction.
but here i have different band structures and do not know why this occurs.
below i attached input of Si unit & 2x2x2 supercell.
*input for Si 2x2x2 supercell*
# self-consistent calculation
cat > si.scf.in << EOF
&control
calculation='scf'
restart_mode='from_scratch',
prefix='si'
pseudo_dir = '/home/physics/Desktop/espresso-5.0.1/pseudo/',
outdir='/home/physics/tmp/'
/
&system
ibrav = 2,
A = 10.7952 ,
B = 10.7952 ,
C = 10.7952 ,
cosAB = 0 ,
cosAC = 0 ,
cosBC = 0 ,
nat = 16,
ntyp = 1,
ecutwfc = 18.0 ,
ecutrho = 72 ,
occupations = 'smearing' ,
degauss = 0.01 ,
smearing = 'gaussian' ,
/
&ELECTRONS
conv_thr = 1.0d-6,
mixing_beta = 0.3,
/
ATOMIC_SPECIES
Si 28.08600 Si.pz-mt_fhi.UPF
ATOMIC_POSITIONS angstrom
Si 0.000000000 0.000000000 0.000000000
Si 1.349401350 1.349401350 1.349401350
Si -2.698802700 2.698802700 0.000000000
Si -1.349401350 4.048204050 1.349401350
Si 0.000000000 2.698802700 2.698802700
Si 1.349401350 4.048204050 4.048204050
Si -2.698802700 5.397605400 2.698802700
Si -1.349401350 6.747006750 4.048204050
Si -2.698802700 0.000000000 2.698802700
Si -1.349401350 1.349401350 4.048204050
Si -5.397605400 2.698802700 2.698802700
Si -4.048204050 4.048204050 4.048204050
Si -2.698802700 2.698802700 5.397605400
Si -1.349401350 4.048204050 6.747006750
Si -5.397605400 5.397605400 5.397605400
Si -4.048204050 6.747006750 6.747006750
K_POINTS automatic
2 2 2 0 0 0
EOF
# band structure calculation along high-symmetry lines
cat > si.band.in << EOF
&control
calculation='bands'
pseudo_dir = '/home/physics/Desktop/espresso-5.0.1/pseudo/',
outdir='/home/physics/tmp/',
prefix='si'
/
&system
ibrav = 2,
A = 10.7952 ,
B = 10.7952 ,
C = 10.7952 ,
cosAB = 0 ,
cosAC = 0 ,
cosBC = 0 ,
nat = 16,
ntyp = 1,
ecutwfc = 18.0 ,
ecutrho = 72 ,
occupations = 'smearing' ,
degauss = 0.01 ,
smearing = 'gaussian' ,
nbnd = 50,
/
&ELECTRONS
conv_thr = 1.0d-6 ,
mixing_beta = 0.3 ,
/
ATOMIC_SPECIES
Si 28.08600 Si.pz-mt_fhi.UPF
ATOMIC_POSITIONS angstrom
Si 0.000000000 0.000000000 0.000000000
Si 1.349401350 1.349401350 1.349401350
Si -2.698802700 2.698802700 0.000000000
Si -1.349401350 4.048204050 1.349401350
Si 0.000000000 2.698802700 2.698802700
Si 1.349401350 4.048204050 4.048204050
Si -2.698802700 5.397605400 2.698802700
Si -1.349401350 6.747006750 4.048204050
Si -2.698802700 0.000000000 2.698802700
Si -1.349401350 1.349401350 4.048204050
Si -5.397605400 2.698802700 2.698802700
Si -4.048204050 4.048204050 4.048204050
Si -2.698802700 2.698802700 5.397605400
Si -1.349401350 4.048204050 6.747006750
Si -5.397605400 5.397605400 5.397605400
Si -4.048204050 6.747006750 6.747006750
K_POINTS
36
0.5 0.5 0.5 1
0.4 0.4 0.4 2
0.3 0.3 0.3 3
0.2 0.2 0.2 4
0.1 0.1 0.1 5
0.0 0.0 0.0 6
0.0 0.0 0.1 7
0.0 0.0 0.2 8
0.0 0.0 0.3 9
0.0 0.0 0.4 10
0.0 0.0 0.5 11
0.0 0.0 0.6 12
0.0 0.0 0.7 13
0.0 0.0 0.8 14
0.0 0.0 0.9 15
0.0 0.0 1.0 16
0.0 0.1 1.0 17
0.0 0.2 1.0 18
0.0 0.3 1.0 19
0.0 0.4 1.0 20
0.0 0.5 1.0 21
0.0 0.6 1.0 22
0.0 0.7 1.0 23
0.0 0.8 1.0 24
0.0 0.9 1.0 25
0.0 1.0 1.0 26
0.0 0.9 0.9 27
0.0 0.8 0.8 28
0.0 0.7 0.7 29
0.0 0.6 0.6 30
0.0 0.5 0.5 31
0.0 0.4 0.4 32
0.0 0.3 0.3 33
0.0 0.2 0.2 34
0.0 0.1 0.1 35
0.0 0.0 0.0 36
EOF
*Si Unitcell:*
# self-consistent calculation
cat > si.scf.in << EOF
&control
calculation='scf'
restart_mode='from_scratch',
prefix='si'
pseudo_dir = '$PSEUDO_DIR/',
outdir='$TMP_DIR/'
/
&system
ibrav= 2,
A = 5.397,
B =5.397,
C = 5.397,
cosAB = 0 ,
cosAC = 0 ,
cosBC = 0 , nat= 2, ntyp= 1,
ecutwfc =18.0, occupations = 'smearing', degauss = 0.01 smearing =
'gaussian' ,
/
&electrons
conv_thr = 1.0d-6
mixing_beta = 0.3
/
ATOMIC_SPECIES
Si 28.086 Si.pz-vbc.UPF
ATOMIC_POSITIONS angstrom
Si 0.0000000000 0.0000000000 0.0000000000
Si 1.3494013500 1.3494013500 1.3494013500
K_POINTS automatic
6 6 6 0 0 0
EOF
# band structure calculation along high-symmetry lines
cat > si.band.in << EOF
&control
calculation='bands'
pseudo_dir = '$PSEUDO_DIR/',
outdir='$TMP_DIR/',
prefix='si'
/
&system
ibrav= 2,
A = 5.397,
B =5.397,
C = 5.397,
cosAB = 0 ,
cosAC = 0 ,
cosBC = 0 ,
nat= 2, ntyp= 1,
ecutwfc =18.0, nbnd = 28,
/
&electrons
/
ATOMIC_SPECIES
Si 28.086 Si.pz-vbc.UPF
ATOMIC_POSITIONS angstrom
Si 0.0000000000 0.0000000000 0.0000000000
Si 1.3494013500 1.3494013500 1.3494013500
K_POINTS
36
0.5 0.5 0.5 1
0.4 0.4 0.4 2
0.3 0.3 0.3 3
0.2 0.2 0.2 4
0.1 0.1 0.1 5
0.0 0.0 0.0 6
0.0 0.0 0.1 7
0.0 0.0 0.2 8
0.0 0.0 0.3 9
0.0 0.0 0.4 10
0.0 0.0 0.5 11
0.0 0.0 0.6 12
0.0 0.0 0.7 13
0.0 0.0 0.8 14
0.0 0.0 0.9 15
0.0 0.0 1.0 16
0.0 0.1 1.0 17
0.0 0.2 1.0 18
0.0 0.3 1.0 19
0.0 0.4 1.0 20
0.0 0.5 1.0 21
0.0 0.6 1.0 22
0.0 0.7 1.0 23
0.0 0.8 1.0 24
0.0 0.9 1.0 25
0.0 1.0 1.0 26
0.0 0.9 0.9 27
0.0 0.8 0.8 28
0.0 0.7 0.7 29
0.0 0.6 0.6 30
0.0 0.5 0.5 31
0.0 0.4 0.4 32
0.0 0.3 0.3 33
0.0 0.2 0.2 34
0.0 0.1 0.1 35
0.0 0.0 0.0 36
EOF
*thank you *
*_________________________*
*Muthu.VMadurai Kamaraj University__________________________*
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20140122/edda2a60/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: sibands.ps
Type: application/postscript
Size: 112662 bytes
Desc: not available
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20140122/edda2a60/attachment.ps>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: siunitcell.ps
Type: application/postscript
Size: 20179 bytes
Desc: not available
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20140122/edda2a60/attachment-0001.ps>
More information about the users
mailing list