I’m a new user of abinit. After calculate the band structure of CaO, I’ve some questions on the result. The band structure of the primitive cell of CaO is indirect band gap, and it is the same as the other calculationhttp://iopscience.iop.org/1742-6596/100/4/042006 . However, the band structure of the 2*2*2 supercell of CaO is direct band gap, the figure and input file are as follows. The xred of supercell of CaO is generated from Material studio.
Would you please help me?
Thank you in advance.
The band structure figure:
The input file of primitive cell of CaO
CaOprimituve_cell.in- (754 Bytes) Downloaded 228 times
ndtset 2
#dataset 1
kptopt 1
nshiftk1 4
shiftk1
0.5 0.5 0.5
0.5 0.0 0.0
0.0 0.5 0.0
0.0 0.0 0.5
ngkpt1 8 8 8
prtden1 1
toldfe1 1.0d-6
#dataset2: the band structure
iscf2 -2 #SCF cycle:CG based on the minim of the energy(non-selfconsistent calcylation)
getden2 -1
kptopt2 -3
nband2 16
ndivk2 10 12 17
kptbounds2
0.5 0 0 #L
0 0 0 #Gamma
0 0.5 0.5 #X
1 1 1 #Gamma in another cell
tolwfr2 1.0d-16
enunit2 0 #0---hatree
#Definition of the unit cell
#chkprim 0
diemac 12
acell 6.43 6.43 6.43
angdeg 60 60 60
#rprim 0 0.5 0.5
# 0.5 0 0.5
# 0.5 0.5 0
ntypat 2
znucl 20 8
natom 2
typat 1 2
xred 0 0 0
0.5 0.5 0.5
ecut 40.0
nstep 45
The input file of 2*2*2 supercell of CaO
- 222supercell.in
- (1.4 KiB) Downloaded 238 times
ndtset 2
#dataset 1：usual self-consistent calculation
kptopt1 1
nshiftk1 4
shiftk1
0.5 0.5 0.5
0.5 0 0
0 0.5 0
0 0 0.5
ngkpt1 4 4 4
prtden1 1
toldfe1 1.0d-6
#dataset2: the band structure
iscf2 -2 #SCF cycle:CG based on the minim of the energy(non-selfconsistent calcylation)
getden2 -1
kptopt2 -3
nband2 48
ndivk2 10 12 17
kptbounds2
0.5 0 0 #L
0 0 0 #Gamma
0 0.5 0.5 #X
1 1 1 #Gamma in another cell
tolwfr2 1.0d-16
enunit2 0 #0---hatree
#Definition of the unit cell
chkprim 0
#angdeg 90 90 90
rprim 0 1 1
1 0 1
1 1 0
acell 9.093 9.093 9.093 #CaO lattice constant a=4.81 Angstrom,is equal to 9.093 bohr
ntypat 2
znucl 20 8
natom 16
typat 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2
xred
-0.00000 -0.00000 0.00000
0.25000 0.25000 0.25000
0.50000 -0.00000 0.00000
0.75000 0.25000 0.25000
-0.00000 0.50000 0.00000
0.25000 0.75000 0.25000
0.50000 0.50000 0.00000
0.75000 0.75000 0.25000
-0.00000 -0.00000 0.50000
0.25000 0.25000 0.75000
0.50000 -0.00000 0.50000
0.75000 0.25000 0.75000
-0.00000 0.50000 0.50000
0.25000 0.75000 0.75000
0.50000 0.50000 0.50000
0.75000 0.75000 0.75000
ecut 40.0
nstep 45
Best regards.
Qiaofen Li
qiaofen0630@163.com
School of Electronic Science and Engineering
Southeast University
2# SiPaiLou
Nanjing
Jiangsu, China