Author Topic: level alingment  (Read 2478 times)

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Offline Khattab

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level alingment
« on: August 2, 2015, 01:43 »
Dear All,
I carried out some electron transport calculations and when i summit the manuscript, i got the following comment,

1- There is no discussion of the incorrect level alignment resulting from an LDA calculation, that is routinely corrected in similar calculations in the literature 
 How can reply to this comment,
Any help???
Regards
Khattab

Offline Anders Blom

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Re: level alingment
« Reply #1 on: August 2, 2015, 23:57 »
I don't quite understand that comment, alignment of what levels? What is your system, what levels could we be talking about? Of course LDA underestimates the band gap (and perhaps also HOMO-LUMO gaps in molecules), and there are ways to adjust for this, but not by just "corrections", rather you can use methods like LDA+U or MGGA (or even HSE), but that's a different story, then you have to re-run all simulations. The key point is, in my opinion, that if any of your conclusions critically depend on the "level alignment" - whatever it means - then it's best to check if it's an artifact of LDA, or the same would happen regardless if the band gap or HOMO-LUMO gap was corrected.

Offline Khattab

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Re: level alingment
« Reply #2 on: August 7, 2015, 14:11 »
Dear Dr Anderson blom,
Firstly thank you very much for your valuable replies for all my pasts, which learned me alot, for this question, my system is a two porbe system consisting from two gold electrode and an organic molecule sandwiched between them, i calculate I-V curve and tried to explain it through Transmission spectra and MPSH and HLG, when i summit my manuscript , i got this replay.

I hope, the situation be clear for you now,
Regards,
Khattab