[DFTB-Plus-User] Problem with :Relative Poisson Error: NaN"

[Enlong Liu]

Dear Gabriele,

I checked my input and the .skf, it seems that I used a wrong set of .skf
file for the atom-pair interaction. And for the contact part calculation,
the SCC did not converge either. I changed the .skf files and re-calculated
the contact part, then I am waiting for the result. For the PBC parts, I
keep it unchanged. As for the potential file, I haven't checked yet. I will
have a look on that and give the feedback to you.

Thanks a lot for your reply!

Kind regards,


2014-07-16 14:28 GMT+08:00 Gabriele Penazzi <
gabriele.penazzi at bccms.uni-bremen.de>:

>  On 07/11/2014 09:58 PM, Enlong Liu wrote:
>
>   Dear DFTB+ users,
>
>  I want to calculation the transmission function of a contact made of Si
> slab and BNT. But in the output file, the "Relative Poisson Error" term
> gives NaN, instead of a number which is under the tolerance I set in the
> input file. And thus the transmission function gives NaN as well. Could any
> one tell me where the problem comes from?
>
>  In the attachment are relative files I used to do the calculation,
> including input, output, tunnelling data and the geometry file.
>
>  By the way, the input file works for previous calculation for the
> contact made of Ag and BNT, I just changed the structure and the
> corresponding partition and numbering of the geometry.
>
>
> Hi Enlong,
>
> do you use parameters from a freely distributed set? I cannot try to
> replicate your calculation without parameters.
>
> Please note that this case is quite different from Ag/BNT as metal
> electrodes behaves generally better. Semiconducting ones need generally
> long buffers due to the poor screening. Therefore you can expect this
> calculaiton to be more tricky than Ag/BNT, even though these arguments are
> more relevant with applied bias.
>
> That said, there could be some problem in the boundary conditions as the
> Poisson shouldn't behave like this. In the past weeks we spot some problems
> in periodic systems. But in that case something should have happened in the
> Ag/BNT calculation as well. Did you check the potential output in the
> Ag/BNT calculation you made? Did you notice anything strange there?
>
> Cheers,
> Gabriele
>
>
>
>  Thanks a lot for your help!
>
>  Best regards,
>
> --
>  Faculty of Engineering at K.U. Leuven
> BIOTECH at TU Dresden
>  Email: liuenlong20 at gmail.com; enlong.liu at student.kuleuven.be;
> enlong.liu at biotech.tu-dresden.de
> Mobile Phone: +4917666191322
> Mailing Address: Zi. 0108R, Budapester Straße 24, 01069, Dresden, Germany
>
>
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>
>
> --
> Dr. Gabriele Penazzi
> BCCMS - University of Bremen
> http://www.bccms.uni-bremen.de/http://sites.google.com/site/gabrielepenazzi/
>
> phone: +49 (0) 421 218 62337
> fax: +49 (0) 421 218 62770
>
>
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>


-- 
Faculty of Engineering at K.U. Leuven
BIOTECH at TU Dresden
Email: liuenlong20 at gmail.com; enlong.liu at student.kuleuven.be;
enlong.liu at biotech.tu-dresden.de
Mobile Phone: +4917666191322
Mailing Address: Zi. 0108R, Budapester Straße 24, 01069, Dresden, Germany
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