[DFTB-Plus-User] DFTB+NEGF with a gate contact

[Yuranan Hanlumyuang]

Hi,
   I have some basic questions about NEGF calculations with three contacts,
using the Poisson box

(1) Why is in the code, the bias direction is set to the x-direction. In
the manual, it's suggested that
the transport direction is the z-direction, while the gate is y-dir.
However, in the  source code  poisson.F90
where the gate  direction is  automatically set to y-dir, and the bias is
set to x-dir.

(2) What are the criteria for the gate distance (i.e. Rmin_Gate)?
Sometimes, I got a warning message
that "WARNING: Gate Distance too large!". I have looked around the source
code, but still couldn't figured
out which section  decides the value of this parameter.

(3) I've missed the the discussion on the bugs of DFTB+NEGF version r4198,
and how they
are fixed in version r4305. Is version r4198 containing bugs on the
three-contacts sections of the code?
If you could repost the old threads, I would be really appreciated. I am
using version r4198...

Yuranan Hanlumyuang
University of Houston
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