[DFTB-Plus-User] surface slab calculation don't converge

[malahmer at umbb.dz]

dear dftb user's
i have tried to use the dftb code to study the properties of polar ZnO surface. however the scc calculations don't converge
i have used the next input file:

Geometry = GenFormat {
 66  S
 O  Zn H 
   1  3    .00000   .00000   .25000
   2  1    .00000  1.89763  2.68800
   3  2    .00000   .00000  2.01062
   4  2    .00000  1.89763  4.69862
   5  3   3.28680   .00000   .25000
   6  1   3.28680  1.89763  2.68800
   7  2   3.28680   .00000  2.01062
   8  2   3.28680  1.89763  4.69862
   9  3   6.57360   .00000   .25000
  10  1   6.57360  1.89763  2.68800
  11  2   6.57360   .00000  2.01062
  12  2   6.57360  1.89763  4.69862
  13  3  -1.64340  2.84645   .25000
  14  1  -1.64340  4.74409  2.68800
  15  2  -1.64340  2.84645  2.01062
  16  2  -1.64340  4.74409  4.69862
  17  3   1.64340  2.84645   .25000
  18  1   1.64340  4.74409  2.68800
  19  2   1.64340  2.84645  2.01062
  20  2   1.64340  4.74409  4.69862
  21  3   4.93020  2.84645   .25000
  22  1   4.93020  4.74409  2.68800
  23  2   4.93020  2.84645  2.01062
  24  2   4.93020  4.74409  4.69862
  25  1    .00000   .00000  5.37600
  26  1    .00000  1.89763  8.06400
  27  2    .00000   .00000  7.38662
  28  2    .00000  1.89763 10.07462
  29  1   3.28680   .00000  5.37600
  30  1   3.28680  1.89763  8.06400
  31  2   3.28680   .00000  7.38662
  32  2   3.28680  1.89763 10.07462
  33  1   6.57360   .00000  5.37600
  34  1   6.57360  1.89763  8.06400
  35  2   6.57360   .00000  7.38662
  36  2   6.57360  1.89763 10.07462
  37  1  -1.64340  2.84645  5.37600
  38  1  -1.64340  4.74409  8.06400
  39  2  -1.64340  2.84645  7.38662
  40  2  -1.64340  4.74409 10.07462
  41  1   1.64340  2.84645  5.37600
  42  1   1.64340  4.74409  8.06400
  43  2   1.64340  2.84645  7.38662
  44  2   1.64340  4.74409 10.07462
  45  1   4.93020  2.84645  5.37600
  46  1   4.93020  4.74409  8.06400
  47  2   4.93020  2.84645  7.38662
  48  2   4.93020  4.74409 10.07462
  49  1    .00000   .00000 10.75200
  50  1    .00000  1.89763 13.44000
  51  2    .00000   .00000 12.76262
  52  1   3.28680   .00000 10.75200
  53  1   3.28680  1.89763 13.44000
  54  2   3.28680   .00000 12.76262
  55  1   6.57360   .00000 10.75200
  56  1   6.57360  1.89763 13.44000
  57  2   6.57360   .00000 12.76262
  58  1  -1.64340  2.84645 10.75200
  59  1  -1.64340  4.74409 13.44000
  60  2  -1.64340  2.84645 12.76262
  61  1   1.64340  2.84645 10.75200
  62  1   1.64340  4.74409 13.44000
  63  2   1.64340  2.84645 12.76262
  64  1   4.93020  2.84645 10.75200
  65  1   4.93020  4.74409 13.44000
  66  2   4.93020  2.84645 12.76262
    0.0000000000E+00    0.0000000000E+00    0.0000000000E+00
    9.86064505577087    0.0000000000E+00    0.0000000000E+00
   -3.28688168528543    5.69304607688769    0.0000000000E+00
    0.0000000000E+00    0.0000000000E+00   80.0000000000
}
Driver = ConjugateGradient{
   LatticeOpt = No
   AppendGeometries = Yes
   MaxForceComponent [eV/AA]= 0.06
   MaxSteps = 0
}

Hamiltonian = DFTB {
  SCC = Yes
  SCCTolerance = 1.000000000000000E-003
  MaxSCCIterations = 30
  EwaldParameter = 0.02
    Mixer = Broyden {
  MixingParameter = 0.1
  }
  MaxAngularMomentum = {
   Zn = "d"
    O = "p"
    H = "s"
  }
  Charge = 0
 
  Eigensolver = DivideAndConquer {}

  Filling = Fermi {
    Temperature [Kelvin] = 100.000000000000000E-000
  }
  SlaterKosterFiles = {
    O-O = "O-O.skf"
    O-Zn = "O-Zn.skf"
    Zn-O = "Zn-O.skf"
    Zn-Zn = "Zn-Zn.skf"
    H-H = "H-H.skf"
    O-H = "O-H.skf"
    H-O = "H-O.skf"
    H-Zn = "H-Zn.skf"
    Zn-H = "Zn-H.skf"
  }
  KPointsAndWeights = SupercellFolding{
   5    0   0
   0    7   0
   0    0   1
  0.0  0.0 0.0
  }
  }
  Options = {
  WriteAutotestTag = Yes
}
ParserOptions = {
  ParserVersion = 4
}

i have changed the ewald parameter as well as k point mesh and vaccum regionlenght bur without results
if any one has an idea please let me know
best regards