[DFTB-Plus-User] SCC convergence problem

[yangming]

Dear All,

 

I am a beginner of DFTB+. Currently, I use DFTB+ to calculate ZnO band structure, and got a warning message as following:

 

********************************************************************************
** Geometry step:    0
********************************************************************************

  iSCC Total electronic   Diff electronic      SCC error
    1   -0.15653001E+02    0.00000000E+00    0.72663710E-02

 Total Energy:                         -15.519984
 Total Mermin free energy:             -15.519984
WARNING!
-> SCC is NOT converged, maximal iterations exceeded

 

________________

 

Any one there help me to fix this problem? All comments are highly appreciated.

 

Thanks.

 

Kevin

_____________________________

 

The input parameters for calculating this band structure is: 

 

Geometry = GenFormat {
     4  S
 Zn  O
    1 1      0.10584444      1.78119521      0.07906531
    2 2      0.10773915      1.78010232      1.89484115
    3 1      1.48962855      0.98224506      2.65866079
    4 2      1.48773384      0.98333796      4.47443662
      0.00000000      0.00000000      0.00000000
      2.76344027     -1.59547299      0.00000000
      0.00000000      3.19094597      0.00000000
      0.00000000      0.00000000      5.15919095
}
Driver = {}
Hamiltonian = DFTB {
  SCC = Yes
  SCCTolerance = 1.0e-5
  MaxSCCIterations = 1
  Mixer = Broyden {
    MixingParameter = 0.2
    CachedIterations = -1
    InverseJacobiWeight = 1.000000000000000E-002
    MinimalWeight = 1.00000000000000
    MaximalWeight = 100000.000000000
    WeightFactor = 1.000000000000000E-002
  }
  KPointsAndWeights = KLines {
1 0.0 0.0 0.5
30 -0.333333 0.66666667 0.5
30 -0.333333 0.66666667 0.0
30 0.0 0.0 0.0
30 0.0 0.5 0.0
  }
  SlaterKosterFiles = {
    Zn-Zn = "Zn-Zn.skf" #(these parameters are from znorg-0-1 set)
    Zn-O  = "Zn-O.skf"
    O-Zn  = "O-Zn.skf"
    O-O   = "O-O.skf"
  }
  MaxAngularMomentum = {
    Zn = "d"
    O  = "p"
  }
  Charge = 0.0
  SpinPolarisation = {}
  Filling = Fermi {
    Temperature = 1.000000000000000E-008
    IndependentKFilling = No
  }
  ElectricField = {}
  OrbitalResolvedSCC = No
  ReadInitialCharges = Yes
  Eigensolver = DivideAndConquer {}
  OldSKInterpolation = No
  OrbitalPotential = {}
  Dispersion = {}
}
ParserOptions = {
  ParserVersion = 3
  WriteHSDInput = Yes
  WriteXMLInput = No
  StopAfterParsing = No
}
Options = {
  WriteEigenvectors = Yes
  WriteAutotestTag = No
  WriteDetailedXML = Yes
  WriteResultsTag = Yes
  WriteDetailedOut = Yes
  WriteBandOut = Yes
  AtomResolvedEnergies = Yes
  RestartFrequency = 0
  RandomSeed = 0
  CalculateForces = No
}


The input parameters of static calculations to get the ground state charge density is :

 

Geometry = GenFormat {
        4  S
 Zn  O
    1 1      0.10584444      1.78119521      0.07906531
    2 2      0.10773915      1.78010232      1.89484115
    3 1      1.48962855      0.98224506      2.65866079
    4 2      1.48773384      0.98333796      4.47443662
      0.00000000      0.00000000      0.00000000
      2.76344027     -1.59547299      0.00000000
      0.00000000      3.19094597      0.00000000
      0.00000000      0.00000000      5.15919095
}
Driver =  {}
Hamiltonian = DFTB {
  SCC = Yes
  SCCTolerance = 1.0e-5
  KPointsAndWeights = SupercellFolding {
9 0 0
0  9 0
0  0 6
0.0 0.0 0.5
  }
  SlaterKosterFiles = {
    Zn-Zn = "Zn-Zn.skf"
    Zn-O  = "Zn-O.skf"
    O-Zn  = "O-Zn.skf"
    O-O   = "O-O.skf"
  }
  MaxAngularMomentum = {
    Zn = "d"
    O  = "p"
  }
  Charge = 0.0
 }


 
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