[Pw_forum] Problem with the Band Structure Calculation

[潘登]

Dear All,

   I was trying to calculate the band structure of the BaNi2As2 which
had been calculated in the paper 0809.0499v2 on the arxiv.I could not
repeat the same struture.The  BaNi2As2 occurs in a body centered
tetragonal structure (I4/mmm) with Ba,Ni and As at the positions
2a(0,0,0),4d (0.5,0,0.25)and 4e(0,0,z).Here z equels 0.3476 by the
experimental result.The lattice parameters are a=4.112 A and c=11.54
A.
Any comment about my input of this system?
my input of scf run:

 &control
     calculation = 'scf'
     restart_mode='from_scratch'
     prefix='BaNiAs',
     pseudo_dir = '/disk2/xgwan/Quantum-Espresso/espresso-4.0.3/pseudo/',
     outdir='/disk2/xgwan/tmp/'
 /
 &system
     ibrav=6,
     celldm(1)=7.7702,
     celldm(3)=2.806,
     nat=10,
     ntyp=3,
     ecutwfc = 40.0,
     ecutrho = 400.0,
     occupations= 'tetrahedra'
 /
 &electrons
     diagonalization = 'cg'
     mixing_beta = 0.7
     conv_thr =  1.0d-6
 /
ATOMIC_SPECIES
 Ba 137.327 Ba.pbe-nsp-van.UPF
 Ni 58.6934 Ni.pbe-nd-rrkjus.UPF
 As 74.9216 As.pbe-n-van.UPF
ATOMIC_POSITIONS crystal
 Ba 0.0000 0.0000  0.0000
 Ba 0.5000 0.5000  0.5000
 Ni 0.0       0.5        0.25
 Ni 0.5       0.0        0.75
 Ni 0.5       0.0        0.25
 Ni 0.0       0.5        0.75
 As 0.0000 0.0000  0.3476
 As 0.0000 0.0000  0.6524
 As 0.5000 0.5000  0.8476
 As 0.5000 0.5000  0.1524
K_POINTS {automatic}
  8 8 8 0 0 0

And my input of band calculation ,bands.x,plotband.x if helps:
input of band calculation
 &control
     calculation = 'bands'
     prefix='BaNiAs',
     pseudo_dir = '/disk2/xgwan/Quantum-Espresso/espresso-4.0.3/pseudo/',
     outdir='/disk2/xgwan/tmp/'
     wf_collect=.true.
 /
 &system
     ibrav=6,
     celldm(1)=7.7702,
     celldm(3)=2.806,
     nat=10,
     ntyp=3,
     ecutwfc = 40.0,
     ecutrho = 400.0,
     occupations= 'tetrahedra'
 /
 &electrons
     diagonalization = 'cg'
     mixing_beta = 0.7
     conv_thr =  1.0d-6
 /
ATOMIC_SPECIES
 Ba 137.327 Ba.pbe-nsp-van.UPF
 Ni 58.6934 Ni.pbe-nd-rrkjus.UPF
 As 74.9216 As.pbe-n-van.UPF
ATOMIC_POSITIONS crystal
Ba 0.5000 0.5000 0.5000
Ni 0.5000 0.0000 0.2500
Ni 0.0000 0.5000 0.2500
Ni 0.0000 0.5000 0.7500
Ni 0.5000 0.0000 0.7500
As 0.0000 0.0000 0.3476
As 0.0000 0.0000 0.6524
As 0.5000 0.5000 0.8476
As 0.5000 0.5000 0.1524
K_POINTS
31
-0.50  0.50  0.50  1
-0.45  0.45  0.45  2
-0.40  0.40  0.40  3
-0.35  0.35  0.35  4
-0.30  0.30  0.30  5
-0.25  0.25  0.25  6
-0.20  0.20  0.20  7
-0.15  0.15  0.15  8
-0.10  0.10  0.10  9
-0.05  0.05  0.05  10
 0.00  0.00  0.00  11
 0.00  0.00  0.05  12
 0.00  0.00  0.10  13
 0.00  0.00  0.15  14
 0.00  0.00  0.20  15
 0.00  0.00  0.25  16
 0.00  0.00  0.30  17
 0.00  0.00  0.35  18
 0.00  0.00  0.40  19
 0.00  0.00  0.45  20
 0.00  0.00  0.50  21
 0.05  0.05  0.45  22
 0.10  0.10  0.40  23
 0.15  0.15  0.35  24
 0.20  0.20  0.30  25
 0.25  0.25  0.25  26
 0.20  0.30  0.20  27
 0.15  0.35  0.15  28
 0.10  0.40  0.10  29
 0.05  0.45  0.05  30
 0.0   0.50  0.0   31

input of bands.x
 &inputpp
    prefix  = 'BaNiAs'
    outdir = '/disk2/xgwan/tmp/'
    filband = 'bands.dat'
 /
 input of plotband.x
bands.dat
2 17
bands.xmgr
bands.ps
10.5264
1.0 10.5264

With these inputs I could not get the same band structure as the paper
did.I am appreciate for any suggustion and comments.
Please tell me where I was wrong or which detail I ignored.

Have a nice day.

Deng Pan
Nanjing Unversity