charged electrod ATK12.2.2

[tanxj]

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!

[Nordland]

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.

[tanxj]

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.

[baizq]

My question is whether the electrode copy part belongs to the "central region" or not... Does the central region mean scattering region or interaction region? If we dope the electrode, will the electrode copy also be doped?

[Anders Blom]

The electrode copy is part of the central region which is defined as the part of the device where the Hamiltonian and density matrix (and effective potential) are computed self-consistently and thus deviate from the bulk. So the doping will not be copied into the electrode copy.

[baizq]

Thanks Anders. Then the question is how the additional charges in electrodes are treated in the calculation. Will they enter the self-consistent calculation of the electrode? or just "rigidly" shifting the fermi level to some extent which is determined by the integration of occupation of the bulk-like electrode material?

[Anders Blom]

It's not "or just", but rather "and therefore".

[baizq]

Got it. Thanks!