The ABINIT Users Mailing List ( CLOSED )

["Anglade Pierre-Matthieu" <anglade@gmail.com>]

Dear A. Andika,

>
> About definition of k-points, I want to know how to do this for zinc blende
> structure like GaAs. In abinit tutorial, I only see the explanation for fcc 
> and
> bcc structure about their nshiftk and shiftk parameter value.
>

In every case, you can rely on "prtkpt" to help you set the best
possible k-point mesh.


> About optimization of lattice parameter, I want to know how to give the 
> right
> value for each parameter, like optcell or ionmov. I got suggestion to use
> optcell=2 for zinc blende structure, but I want to know why

The best to understand both the suggestions you get about this problem
and my  answer to your first question is to have a look at
http://www.abinit.org/Infos_v5.5/input_variables/keyhr.html where all
input variables for Abinit are described.

Regards

PMA



>
> This is my code
> ------------------------------------------------------------------------------
> ndtset 5
>
> #Optimization of the lattice parameters
> optcell 2
> ionmov  3
> ntime  10
> dilatmx 1.05
> ecutsm  0.5
>
> #Definition of the k-point grids
> kptopt 1          # Option for the automatic generation of k points, taking
>                  # into account the symmetry
> nshiftk 1         # of the reciprocal space (that form a BCC lattice !),
>                  # repeated four times, with different shifts :
> shiftk 0.5 0.5 0.5
>
> ngkpt1  2 2 2     # Definition of the different grids
> ngkpt2  4 4 4
> ngkpt3  6 6 6
> ngkpt4  8 8 8
> ngkpt5  10 10 10
> getwfk -1
>
> #Definition of the unit cell and ecut,
> #for which one will have to make a convergence study
> acell 3*10.18
> rprim  0.0  0.5  0.5
>       0.5  0.0  0.5
>       0.5  0.5  0.0
>
> #Definition of the atom types
> ntypat 2
> znucl 31 33
>
> #First dataset : find the optimal bond length of H2, and associated total
> energy
>   natom  2             # There are two atoms
>   typat 1 2
>   xred   0.00 0.00 0.00
>          0.25 0.25 0.25
>
> #Definition of the planewave basis set
> ecut  12.0         # Maximal kinetic energy cut-off, in Hartree
>
>
> #Definition of the SCF procedure
> nstep 10         # Maximal number of SCF cycles
> toldfe 1.0d-6
> diemac 12.0
>
> ---------------------------------------------------------------------------------
> Thank you very much for the attention. I hope you can give me some 
> corrections
> and suggestions
>
> With regard
>
> Andika A.
>



-- 
Pierre-Matthieu Anglade