The ABINIT Users Mailing List ( CLOSED )

[Thierry Deutsch <thierry.deutsch@cea.fr>]

Dear All,

    There are some ideas to compute a charged defect properly based on 
real space basis sets as wavelets.

Please find a reference of a mathematical paper which gives some 
indications:
E. Cancès, A. Deleurence & M. Lewin, / Non-perturbative embedding of 
local defects in crystalline materials. J. Phys.: Condens. Matter 20 
(2008), 294213 (see the web page http://cermics.enpc.fr/~deleuren for 
the pdf file).

We will have a PhD student to implement a method to calculate charged 
defects but nothing is already done!
/
Best Regards,

  Thierry


matthieu verstraete a écrit :
> if your periodic cell is charged the coulomb energy should explode. 
> Abinit can deal with this if a uniform compensating charge is added 
> (http://www.abinit.org/Infos_v5.6/input_variables/vargs.html#charge). 
> In principle you should add corrections to the energy (e.g. Makov and 
> Payne http://prola.aps.org/forward/PRB/v51/i7/p4014_1 although this is 
> far from the best, see also PA Schultz's articles), but these are not 
> present in abinit. This approach is used quite frequently in solid 
> state defect studies, but actually can converge quite badly (even with 
> the corrections) with system size. No real solution has been found yet 
> to get small sizes and converged defect energies etc... Others would 
> tell you to use a finite system cluster code, but then you don't have 
> a very realistic crystal. The jellium background is a better and 
> better approximation as the cell gets bigger of course.
>
> The other option (for finite systems or clusters in abinit) is to use 
> the wavelet Poisson solver (icoultrtmt - note the restrictions on cell 
> size and shape) and remove all interaction with neighboring cells (but 
> if you have a crystal this will not be satisfactory until large cell 
> sizes).
>
> "it's a hard knock life"
>
> Matthieu
>
> On Thu, Sep 11, 2008 at 5:07 PM, Manuel Pérez Jigato 
> <Manuel.PerezJigato@fys.kuleuven.be 
> <mailto:Manuel.PerezJigato@fys.kuleuven.be>> wrote:
>
>     Dear all
>
>     is it possible to calculate charged cells using ABINIT. i mean for
>     defect systems
>     regards
>
>     Manuel Perez Jigato
>     KU Leuven
>
>     Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
>
>
>
>
> --
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Dr. Matthieu Verstraete
>
> European Theoretical Spectroscopy Facility (ETSF) 
> Dpto. Fisica de Materiales, 
> U. del Pais Vasco,            
> Centro Joxe Mari Korta, Av. de Tolosa, 72, Phone: +34-943018393
> E-20018 Donostia-San Sebastian, Spain Fax  : +34-943018390
>
> Mail : matthieu.jean.verstraete@gmail.com 
> <mailto:matthieu.jean.verstraete@gmail.com>
> http://www-users.york.ac.uk/~mjv500 
> <http://www-users.york.ac.uk/%7Emjv500>


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Thierry Deutsch                                                        
Laboratoire de simulation atomistique (L_Sim)
INAC/SP2M                                       Tél:(33) 04 38 78 34 06
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17, Avenue des Martyrs                    mailto:Thierry.Deutsch@cea.fr
38054 GRENOBLE CEDEX 9 FRANCE                  http://inac.cea.fr/L_Sim
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