[DFTB-Plus-User] Fermi level in DOS and Band calculation

[Ben Hourahine]

Hi,

definitely the DOS. The k-points for the band structure aren't normally 
sufficient to correctly
converge the Fermi energy.

Regards

Ben

On 28/08/12 06:43, R.Perez Garcia wrote:
> Dear DFTB specialists,
>
> I have a doubt regarding the Fermi Energy.
> It differ in the DOS calculation and in the subsequent calculation for 
> the Band Structure. Which is more likely to be correct in your opinion?
> Please let me know if you need any further data.
> Best regards: R
>
> DOS:
> Geometry = GenFormat {
>  <<< "geom.gen"
>  }
> Driver = {}
>
> Hamiltonian = DFTB {               # DFTB Hamiltonian
>         SCC = Yes                        # Use NCC
>         SCCTolerance = 1.0e-006            # Tolerance for charge 
> consistence
>         MaxSCCIterations = 200           # Nr. of maximal SCC iterations
>         Mixer = Broyden {}
>         Eigensolver = DivideAndConquer {}
>         MaxAngularMomentum = {           # Maximal l-value of the 
> various species
>         C = "p"
>         H = "s"
>         S = "p"
>         N = "p"
>         O = "p"
>         }
>         Charge = 0.000
>         Dispersion = LennardJones {
>         Parameters = UFFParameters {}
>         }
>         Filling = Fermi {
>         Temperature [K] = 100
>         }
>         SlaterKosterFiles =  Type2FileNames {            # Specifying 
> Slater-Koster files
>          Prefix = '/home/morokuma4/rpg/Rodrigo/slko.5425/'
>          Separator = ""
>          Suffix = ".spl"
>          LowerCaseTypeName = Yes
>         }
>         ReadInitialCharges = No
>         KPointsAndWeights = SupercellFolding {
>          4 0 0
>          0 1 0
>          0 0 1
>          0.5 0.0 0.0
>         }
> Analysis {
>   ProjectStates {
>        Region {
>        Atoms = C
>        ShellResolved = Yes
>        Label = "dos_c"
>        }
>        Region {
>        Atoms = S
>        ShellResolved = Yes
>        Label = "dos_s"
>        }
>        Region {
>        Atoms = Si
>        ShellResolved = Yes
>        Label = "dos_si"
>        }
>        Region {
>        Atoms = N
>        ShellResolved = Yes
>        Label = "dos_n"
>        }
>        Region {
>        Atoms = H
>        ShellResolved = Yes
>        Label = "dos_h"
>        }
>        Region {
>        Atoms = O
>        ShellResolved = Yes
>        Label = "dos_o"
>        }
>        Region {
>        Atoms = 249:313 315:320 335 337 342 345:350 357:421 423:428 443 
> 445 450 453:458
>        ShellResolved = Yes
>        Label = "dos_c_pcbm"
>        }
>        Region {
>        Atoms = 338 354 446 462
>        ShellResolved = Yes
>        Label = "dos_n_pcbm"
>        }
> .....
> BAND:
>
> Geometry = GenFormat {
>  <<< "geom.gen"
>  }
> Driver = {}
> Hamiltonian = DFTB {               # DFTB Hamiltonian
>         SCC = Yes                        # Use NCC
>         SCCTolerance = 1.0e-006            # Tolerance for charge 
> consistence
>         MaxSCCIterations = 1           # Nr. of maximal SCC iterations
>         Mixer = Broyden {}
>         Eigensolver = DivideAndConquer {}
>         MaxAngularMomentum = {           # Maximal l-value of the 
> various species
>         C = "p"
>         H = "s"
>         S = "p"
>         N = "p"
>         O = "p"
>         }
>         Charge = 0.000
>         Dispersion = LennardJones {
>         Parameters = UFFParameters {}
>         }
>         Filling = Fermi {
>         Temperature [K] = 100
>         }
>         SlaterKosterFiles =  Type2FileNames {            # Specifying 
> Slater-Koster files
>          Prefix = '/home/morokuma4/rpg/Rodrigo/slko.5425/'
>          Separator = ""
>          Suffix = ".spl"
>          LowerCaseTypeName = Yes
>         }
> #       ReadInitialCharges = No
>         ReadInitialCharges = Yes
>         KPointsAndWeights = Klines {
>         1 0.0 0.0 0.0 # 0.0.0
>         40 0.5 0.0 0.0 # pi/a
>         }
> }
> Options = {
> #  WriteEigenvectors = No
>   WriteEigenvectors = No
>   WriteAutotestTag = No
> #  WriteDetailedXML = No
>   WriteDetailedXML = No
>   WriteResultsTag = No
>   WriteDetailedOut = Yes
>   WriteBandOut = Yes
>   AtomResolvedEnergies = No
>   RandomSeed = 1
>   ShowFoldedCoords = Yes
>   RestartFrequency = 0
> }


-- 
      Dr. B. Hourahine, SUPA, Department of Physics,
    University of Strathclyde, John Anderson Building,
           107 Rottenrow, Glasgow G4 0NG, UK.
     +44 141 548 2325, benjamin.hourahine at strath.ac.uk
    The University of Strathclyde is a charitable body,
registered in Scotland, with registration number SC015263

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