[Pw_forum] Band structure

[潘登]

Dear all users,
   I have got a 'flat' band structure.I thought it should be wrong.By
'flat' I meant that some bands of my calculation from one point to
another were parallel to the x-axis.The number of parallel bands seems
too big.
   I considered error would happen at 'degauss' value for the smearing
option.Any suggest or comment on the value and the 'flat' band
stucture would be appriciate.
 my input
 &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= 'smearing'
     degauss = 0.03
     smearing = 'marzari-vanderbilt'
 /
 &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

Thanks for all the help.

Deng Pan
Nanjing University