Messages

1

General Questions and Answers / Re: charged electrod ATK12.2.2

« on: July 18, 2012, 12:16 »

Got it! Thanks for your help!

The electrode is a closed system, so you can add charge, and it will remain within this closed system.
The central region is a open system, so if there is too much charge in the system, it will run out in the infinite reservoirs,
if there is too little charge, charge will run in from the infinite reservoirs.

So the answer is no. You can't charge the central region as it does not make sense. Add an extra electron would give you the exact same
result as subtracting three electrons, as it would converge to a solution where it has exactly the correct amount of electrons.
This is the entire idea behind NEGF.

2

General Questions and Answers / Re: Difficult to converge with a large value of charge. NEW!!

« on: July 18, 2012, 12:15 »

Got it! Thanks for your help!

It would certainly be cool if our software could do that!
But with little practical value, since the H+ would attract electrons right away.

We haven't designed for calculating such extreme systems, the changed electrodes are only meant for subtle doping effects. But perhaps it would be worth giving an error message if the value is set too high.

3

General Questions and Answers / Re: Difficult to converge with a large value of charge. NEW!!

« on: July 18, 2012, 09:40 »

I try to simulate a device with the right electrode consisted of H+ ion instead of H atom.

Why do you want to do it?
I'm a little curious because I can't think of a physical system that this would simulate.

4

General Questions and Answers / Difficult to converge with a large value of charge. NEW!!

« on: July 18, 2012, 08:17 »

Dear Supreme ATK Wizards:
I want to calculated the transmission for a two-electrode device with the right one charged as described in the inscript. A converged result is obtained if the charge is not too large (such as 0.1).
However, it's very difficult to converge when the charge  is set as large value (in this work, the charge is expected to be 12.0). As discussed in the previous FAQs, the charged system is expected  to use a lot of k-points and a high temperature to reach a convergence. it is confusing that these tips can't work!
I have two doubts about this puzzle.One is that the value of charge must be small compared to the total amount of electrons, the other one is there are some neglectful algorithmic parameters.
Thanks for you attention and I'm looking forward to your replies!

Sincerely,
X. J. Tan

5

General Questions and Answers / charged electrod ATK12.2.2

« on: July 15, 2012, 15:56 »

Dear all,
The new released ATK 12.2.2 introduces the possibility to use charged electrodes. The right and left electrods can be charged, respectively, and what about the central scattering region? Whether it can be charged like the electrods?
Thanks for your attention!

6

General Questions and Answers / Re: about addtional_charge

« on: July 15, 2012, 13:35 »

Thank you very much!

No.

This is parameter only for tuning the basis set, making it more smooth by including more or less charge in the radial solution. This is more a numerical trick parameter.

7

General Questions and Answers / about addtional_charge

« on: July 15, 2012, 07:12 »

Dear all,
As the manual says: "additional_charge" is one of the parameters that determines the shape of the "ConfinedOrbital".
so, if the additional_charge is set as -1.0 for Oxygen, does it mean that the O atoms in the calculation are O- anions actually?
Thanks for your attention.

Sincerely,
X. J. Tan