[DFTB-Plus-User] R: non-scc transport calculation

[Alessandro Pecchia]

Hi Theodoros,

 

concerning technical details of transport in dftb+ I should also add this reference:

 

A.Pecchia et al. “Theoretical and Computational Chemistry, Volume 17, 2007, Pages 205-232

https://www.sciencedirect.com/science/article/pii/S1380732307800264

 

And there is a chapter in this other book (p153-184):

https://link.springer.com/book/10.1007/b101525

 

 

Regards,

 

Alessandro

 

Da: DFTB-Plus-User [mailto:dftb-plus-user-bounces at mailman.zfn.uni-bremen.de] Per conto di Gabriele Penazzi
Inviato: mercoledì 12 settembre 2018 09:18
A: User list for DFTB+ related questions
Oggetto: Re: [DFTB-Plus-User] non-scc transport calculation

 

Hi Theodoros,

 

this is the reference paper for the NEGF implementation in DFTB+:

http://iopscience.iop.org/article/10.1088/1367-2630/10/6/065022/meta

 

For more technical questions I think that this mailing list (and the mailing list archive) is the best place to ask.

 

Gabriele

 

Il giorno mer 12 set 2018 alle ore 09:09 Theodoros Leontiou <eng.lt at frederick.ac.cy> ha scritto:

Hi Gabriele,

Thanks for your reply. 

 

 

There is a lot of literature about the NEGF formalism.  However, could you please point out which is the most appropriate reference for the theoretical (and perhaps technical) formalism behind the negf in dftb+ ? 

 

 

 

Regards

Theodoros

 

 

On 2018-09-12 09:22, Gabriele Penazzi wrote:

Hi Theodoros,

 

it makes sense, but it may sound surprising depending on how you define "non-scc". In DFTB+, it means that no additional correction on the starting non-scc hamiltonian is added. Therefore density of states and transmission do not depend on Fermi level and potential. The only quantity which should show dependence on those two quantities in a non-scc calculation is the total current, as both fermi level and potential enter the Landauer formula.

 

I can imagine that some other tight binding codes may define as 'non-scc' also a solution which includes somehow finite bias boundary conditions (for example, by adding non-selfconsistently a ramp potential), but this is not the case in DFTB+.

 

Gabriele

 

Il giorno mar 11 set 2018 alle ore 20:49 Theodoros Leontiou <eng.lt at frederick.ac.cy> ha scritto:

Dear dftb+ experts,

I am running some non-scc transport calculations using the transportonly option. Although the results I get look reasonable there is not any dependence on the choice of the Fermi level or potential for the contacts. Is this reasonable? 

Best Regards

Theodoros

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Gabriele Penazzi
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skype: gabriele.penazzi

 

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mobile: +45 51894907
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