[Pw_forum] problem in HSE band structure calculation

[LEUNG Clarence]

Dear all,

I use the HSE function to calculate the band structure of my system. However, I found that the band gap is much smaller than that of other researchers(about 2eV obtained from vasp). I also calculated the PBE band gap, which agrees well with previous reports.

I also attached my scf input file. The pseudopotentials is Norm-conserving.

&SYSTEM
  ecutwfc=30,
  input_dft='hse',
  occupations='smearing',
  smearing = 'gaussian' ,
  degauss = 0.02 ,
  nosym = .true. ,
  vdw_corr = 'DFT-D' ,
  nqx1 = 1,
  nqx2 = 1 ,
  nqx3 = 1 ,
/
&ELECTRONS
  conv_thr=1d-06,
  mixing_beta=0.3d0,
  electron_maxstep = 1000 ,
/
&IONS
  ion_dynamics = 'bfgs',
  bfgs_ndim = 3 ,
/
K_POINTS
84
0.0000000  0.0000000  0.0000000  0.03125
0.0000000  0.1443377  0.0000000  0.06250
0.0000000  0.2886754  0.0000000 0.06250
0.0000000  0.4330131  0.0000000 0.06250
0.0000000 -0.5773508  0.0000000 0.03125
0.1250000  0.0721689  0.0000000 0.0625
0.1250000  0.2165066  0.0000000 0.0625
0.1250000  0.3608443  0.0000000 0.0625
0.1250000  0.5051820  0.0000000 0.0625
0.1250000 -0.5051820  0.0000000 0.0625
0.1250000 -0.3608443  0.0000000 0.0625
0.1250000 -0.2165066  0.0000000 0.0625
0.1250000 -0.0721689  0.0000000 0.0625
0.2500000  0.1443377  0.0000000 0.0625
0.2500000  0.2886754  0.0000000 0.0625
0.2500000  0.4330131  0.0000000 0.0625
0.2500000  0.5773508  0.0000000 0.0625
0.2500000 -0.4330131  0.0000000 0.0625
0.2500000 -0.2886754  0.0000000 0.0625
0.2500000 -0.1443377  0.0000000 0.0625
0.2500000  0.0000000  0.0000000 0.0625
0.3750000  0.2165066  0.0000000 0.0625
0.3750000  0.3608443  0.0000000 0.0625
0.3750000  0.5051820  0.0000000  0.0625
0.3750000  0.6495197  0.0000000  0.0625
0.3750000 -0.3608443  0.0000000  0.0625
0.3750000 -0.2165066  0.0000000  0.0625
0.3750000 -0.0721689  0.0000000  0.0625
0.3750000  0.0721689  0.0000000  0.0625
-0.500000 -0.2886754  0.0000000  0.03125
-0.500000 -0.1443377  0.0000000  0.0625
-0.500000  0.0000000  0.0000000  0.0625
-0.500000  0.1443377  0.0000000  0.0625
-0.500000 -0.8660262  0.0000000  0.03125
        0.0000000000    0.0000000000    0.0000000000    0
        0.0277777778    0.0000000000    0.0000000000    0
        0.0555555556    0.0000000000    0.0000000000    0
        0.0833333333    0.0000000000    0.0000000000    0
        0.1111111111    0.0000000000    0.0000000000    0
        0.1388888889    0.0000000000    0.0000000000    0
        0.1666666667    0.0000000000    0.0000000000    0
        0.1944444444    0.0000000000    0.0000000000    0
        0.2222222222    0.0000000000    0.0000000000    0
        0.2500000000    0.0000000000    0.0000000000    0
        0.2777777778    0.0000000000    0.0000000000    0
        0.3055555556    0.0000000000    0.0000000000    0
        0.3333333333    0.0000000000    0.0000000000    0
        0.3611111111    0.0000000000    0.0000000000    0
        0.3888888889    0.0000000000    0.0000000000    0
        0.4166666667    0.0000000000    0.0000000000    0
        0.4444444444    0.0000000000    0.0000000000    0
        0.4722222222    0.0000000000    0.0000000000    0
        0.5000000000    0.0000000000    0.0000000000    0
        0.4833330000    0.0333330000    0.0000000000    0
        0.4666660000    0.0666660000    0.0000000000    0
        0.4499990000    0.0999990000    0.0000000000    0
        0.4333320000    0.1333320000    0.0000000000    0
        0.4166650000    0.1666650000    0.0000000000    0
        0.3999980000    0.1999980000    0.0000000000    0
        0.3833310000    0.2333310000    0.0000000000    0
        0.3666640000    0.2666640000    0.0000000000    0
        0.3499970000    0.2999970000    0.0000000000    0
        0.3333300000    0.3333300000    0.0000000000    0
        0.3174571429    0.3174571429    0.0000000000    0
        0.3015842857    0.3015842857    0.0000000000    0
        0.2857114286    0.2857114286    0.0000000000    0
        0.2698385714    0.2698385714    0.0000000000    0
        0.2539657143    0.2539657143    0.0000000000    0
        0.2380928571    0.2380928571    0.0000000000    0
        0.2222200000    0.2222200000    0.0000000000    0
        0.2063471429    0.2063471429    0.0000000000    0
        0.1904742857    0.1904742857    0.0000000000    0
        0.1746014286    0.1746014286    0.0000000000    0
        0.1587285714    0.1587285714    0.0000000000    0
        0.1428557143    0.1428557143    0.0000000000    0
        0.1269828571    0.1269828571    0.0000000000    0
        0.1111100000    0.1111100000    0.0000000000    0
        0.0952371429    0.0952371429    0.0000000000    0
        0.0793642857    0.0793642857    0.0000000000    0
        0.0634914286    0.0634914286    0.0000000000    0
        0.0476185714    0.0476185714    0.0000000000    0
        0.0317457143    0.0317457143    0.0000000000    0
        0.0158728571    0.0158728571    0.0000000000    0
        0.0000000000    0.0000000000    0.0000000000    0

Thanks


Clarence

City University of Hong Kong
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