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[Fabien Bruneval <fabien.bruneval@polytechnique.fr>]

Furthermore, I guess that InAs is metallic in LDA. Therefore, you should
add a smearing of the electronic population (keywords occopt and tsmear)
and also increase the number of bands in the LDA calculations.

Good luck.

Fabien






Riad Shaltaf wrote:
> Dear Xiao Deng,
>
> This is normal as you are trying to calculate the gap at k point that
> does not exist in your KSS band structure. To calculate the GW
> correction at specific k point, you must provide the LDA/GGA energies
> and wavefunctions for that point, which is practically included in the
> KSS file. The KSS file that you have calculated does not include Gamma
> point. In order to include it you must avoid using shifted k point grid.
> This is explained in the tutorial.
>
> best regards
>
> Riad
>
> On Thu, 2006-09-14 at 17:17 +0800, Huiyong Deng wrote:
>
> > Dear Abinit user,
> >
> > Employing the GW approximation, these days, I've be calculating the
> > InAs band gap (about 0.34eV). However, the calculation doesn't go on
> > afer calculating the KSS files, and there is no tips about ERRORs.What
> > 's wrong with me?  Can you help me? The input file and .files are as
> > following. Thank you very much!
> >
> > InAs. files
> > --------------
> > InAs.in
> > InAs.out
> > InAsi
> > InAso
> > InAs
> > ../../abinit-4.6.5/Psps_for_tests/lda_fhi/49-In-4d.LDA.fhi
> > ../../abinit-4.6.5/Psps_for_tests/lda_fhi/33-As.LDA.fhi
> > ===========================
> > InAs.in
> > ---------------------------
> > ndtset      3
> >
> > # Definition of parameters for the calculation of the KSS file 
> > nbandkss1   -1         # Number of bands in KSS file (-1 means the
> > maximum possible)
> >
> > kssform 1          #added
> >
> > nband1      9         # Number of (occ and empty) bands to be computed
> > istwfk1      10*1
> >
> > #mpspso 1     #added
> >
> >
> > # Calculation of the screening (epsilon^-1 matrix)
> > optdriver2  3        # Screening calculation
> > getkss2     -1       # Obtain KSS file from previous dataset
> > nband2      17       # Bands to be used in the screening calculation
> > ecutwfn2    2.1      # Cut-off energy of the planewave set to
> > represent the wavefunctions 
> > ecuteps2    3.6      # Cut-off energy of the planewave set to
> > represent the dielectric matrix
> > plasfrq2    16.7 eV  # Imaginary frequency where to calculate the
> > screening
> >
> > # Calculation of the Self-Energy matrix elements (GW corrections)
> > optdriver3  4        # Self-Energy calculation
> > getkss3     -2       # Obtain KSS file from dataset 1
> > getscr3     -1       # Obtain SCR file from previous dataset
> > nband3      30       # Bands to be used in the Self-Energy calculation
> > ecutwfn3     5.0     # Planewaves to be used to represent the
> > wavefunctions
> > ecutsigx3     6.0     # Dimension of the G sum in Sigma_x
> >                     # (the dimension in Sigma_c is controlled by
> > npweps) 
> > nkptgw3      1                # number of k-point where to calculate
> > the GW correction
> > kptgw3                       # k-points
> >  0    0.000    0.000
> > bdgw3       4  5             # calculate GW corrections for bands from
> > 4 to 5
> >
> >
> > # Data common to the three different datasets
> >
> > # Definition of the unit cell: fcc
> > acell  3*11.4        # This is equivalent to   10.217 10.217 10.217
> > rprim  0.0  0.5  0.5   # FCC primitive vectors (to be scaled by acell)
> >       0.5  0.0  0.5   
> >       0.5  0.5  0.0
> >
> > # Definition of the atom types
> > ntypat  2         # There is only one type of atom
> > znucl 49 33          # The keyword "znucl" refers to the atomic number
> > of the 
> >                  # possible type(s) of atom. The pseudopotential(s) 
> >                  # mentioned in the "files" file must correspond
> >                  # to the type(s) of atom. Here, the only type is
> > Silicon.
> >                         
> > # Definition of the atoms
> > natom 2           # There are two atoms
> > typat  1 2        
> >
> > xred              # Reduced coordinate of atoms 
> >      0.0  0.0  0.0
> >      0.25 0.25 0.25
> >
> >
> > # Definition of the k-point grid 
> > kptopt  1            # Option for the automatic generation of k
> > points,
> > nkpt    10
> > ngkpt   4 4 4  
> > nshiftk 4
> > shiftk  0.5 0.5 0.5  # These shifts will be the same for all grids
> >        0.5 0.0 0.0
> >        0.0 0.5 0.0
> >        0.0 0.0 0.5
> >
> > # Use only symmorphic operations 
> > symmorphi 0
> >
> > # Definition of the planewave basis set (at convergence 16 Rydberg 8
> > Hartree)
> > ecut 23          # Maximal kinetic energy cut-off, in Hartree
> >
> > # Definition of the SCF procedure 
> > nstep   20        # Maximal number of SCF cycles
> > toldfe  1.0d-6    # Will stop when this tolerance is achieved on total
> > energy
> > diemac  12.0      # Although this is not mandatory, it is worth to
> >                  # precondition the SCF cycle. The model dielectric
> >                  # function used as the standard preconditioner
> >                  # is described in the "dielng" input variable
> > section.
> >                  # Here, we follow the prescription for bulk silicon.
> >
> >
> >
> >
> > ===================
> > Sincerely
> > Xiao Deng