The ABINIT Users Mailing List ( CLOSED )

[ธนูสิทธิ์ บุรินทร์ประโคน <thanusit@kku.ac.th>]

Dear Wang

From your input file, the number of bands stored in the KSS file is 100 (nbandkss2=100) while the nbands used for the screening and GW correction calculations(nband3, nband4) are 150. This is likely to give incorrect results. The nband3 and nband4 shouldn't exeed the  nbandkss2 (this were discussed earlier in the forum). If they have to be 150 it's better to generate the KSS file with nbandkss2=150 or above.  Please don't forget to repeat the convergence tests with your new KSS file.

Hope this help.

Best wishes,

Thanusit Burinprakhon

On March 31, 2008 12:27:09 AM ICT, wxw079000@utdallas.edu wrote:

> Dear All,
>
> I tried to calculate the InAs band structure using GW correction. The default systme is a semiconductor. The InAs
> band gap is 0.0 eV from LDA calculaiton and the GW correction(5.4.4 Version) is about 0.007 eV, which is very 
> small comparing the experimental value 0.53 eV. Then, I tried to treat the system as a metal, i.e, occopt=7 and 
> tsmear value =0.01(also 0.04,0.05,0.1,0.5), the GW correction is around 0.1 eV.
>
> The following is my input and output file for the GW calculation. Is there any kind person help me with this issue?
>
> Thanks in advance,
>
> Best wishes,
>
> Weichao,Wang
>
>
> Input file
> $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
>
> ndtset 4
>
> kptopt 1 # Option for the automatic generation of k points
> ngkpt 6 6 6 # Density of k points
>
>
> nkpt1 28
> nshiftk1 4
> shiftk1 0.5 0.5 0.5 # This grid is the most economical
> 0.5 0.0 0.0
> 0.0 0.5 0.0
> 0.0 0.0 0.5
> prtden1 1 # Print out density
>
>
> # Dataset2: calculation of kss file
>
> nkpt2 44 # A set of 19 k-points containing Gamma
> nshiftk2 4
> shiftk2 0.0 0.0 0.0 # This grid contains the Gamma point
> 0.0 0.5 0.5
> 0.5 0.0 0.5
> 0.5 0.5 0.0
> istwfk2 44*1 # Option needed for Gamma
> iscf2 -2 # Non self-consistent calculation
> getden2 -1 # Read previous density file
> nband2 10
> nbandkss2 100 # Number of bands to store in KSS file
>
> # Dataset3: Calculation of the screening (epsilon^-1 matrix)
> optdriver3 3 # Screening calculation
> getkss3 -1 # Obtain KSS file from previous dataset
> nband3 150 # Bands to be used in the screening calculation
> ecutwfn3 6.0 # Planewaves to be used to represent the wavefunctions
> ecuteps3 6.0 # Dimension of the screening matrix
> ppmfrq3 16.7 eV # Imaginary frequency where to calculate the screening
>
> # Dataset4: Calculation of the Self-Energy matrix elements (GW corrections)
> optdriver4 4 # Self-Energy calculation
> getkss4 -2 # Obtain KSS file from dataset 1
> getscr4 -1 # Obtain SCR file from previous dataset
> nband4 150 # Bands to be used in the Self-Energy calculation
> ecutwfn4 6.0 # Planewaves to be used to represent the wavefunctions
> ecutsigx4 6.0 # Dimension of the G sum in Sigma_x
> # (the dimension in Sigma_c is controlled by npweps)
> nkptgw4 1 # number of k-point where to calculate the GW correction
> kptgw4 # k-points
> 0.000 0.000 0.000 # (Gamma)
> bdgw4 4 5 # calculate GW corrections for bands from 4 to 5
>
>
> # Definition of the unit cell: fcc
> acell 3*11.434 # 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 two types 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 # They both are of type 1, that is, Silicon.
> xred # Reduced coordinate of atoms
> 0.0 0.0 0.0
> 0.25 0.25 0.25
>
>
> ecut 16.0 
>
>
> symmorphi 0
>
> # Definition of the SCF procedure
> nstep 30 # Maximal number of SCF cycles
> diemac 16.0 # 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.
> tolwfr 1.0d-10
>
> iscf 5