[DFTB-Plus-User] SCC error

Gabriele Penazzi gabriele.penazzi at bccms.uni-bremen.de
Thu Oct 24 10:37:52 CEST 2013

On 10/24/2013 10:06 AM, n.salami at srbiau.ac.ir wrote:
> Dear all,
> I'm trying to calculate the transport properties of p-type SiNW in 100
> direction. I took 4 unitcell of the silicon in x direction for each
> electrodes, separately (4 unitcells * 12 unitcells * 12 unitcells ) and 18
>  unitcells of the silicon in x direction for the device. After that, for
> considering virtually boron doping with 1:4000, I have changed only the
> Slater-Koster file of silicon, "Si-Si.skf"(I have changed the last number
> of second line from 2 to 1.99925).
> An error occurred when I'm solving the electrodes by DFTB+.
>  The error information, input and coordinate files are listed in the
> following, could anyone tell me what's wrong with the calculation ?

Hi Nadia,

are you sure that you have enough memory on your machine?

That's a pretty huge system already for the electrodes. See the manual
in the mixer and options sections for some memory-saving hints.

But even when you get the electrodes done, you'll get in troubles very
soon with the device calculation. 6x6 nm is a terribly large
cross-section for an atomistic method, even for a fully empirical. The
algorithm needs no less than 3N*L (some more, but let's keep it simple)
dense matrices  where N is the number of layers and L the size of a
layer. In your case L is roughly 1.5-2.0 GB.


Dr. Gabriele Penazzi
BCCMS - University of Bremen


phone: +49 (0) 421 218 62337
fax: +49 (0) 421 218 62770

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