Electron Transport Properties

[Tarek Larbi]

When comparing transport coefficients of 3D, 2D, and 1D systems, we need a consistent dimensional normalization. What is the effective thickness of the monolayer and cross-sectional area of the nanotube?

[Aleks]

Dear Tarek,

The question of "what thickness should one use" in 2D materials (or equivalent 1D structure) is somewhat ambiguous as different literature uses different definitions of how to "normalise" the values. I recommend the discussion (and metric) by Wu et al in his article "How to characterize thermal transport capability of 2D materials fairly? – Sheet thermal conductance and the choice of thickness", Chemical Physics Letters 669 (2017) 233–237t, DOI: 10.1016/j.cplett.2016.12.054, but of course there are other ways to go about this. Here is the link:
https://www.sciencedirect.com/science/article/pii/S0009261416310193?via%3Dihub#article

Hope this helps,
Aleks

[Tarek Larbi]

Dear Aleks,
Thank you a lot.
I mean in CRYSTAL what are the considered measure to do dimensional normalization in 2D and 1D systems. I search this information in the manuals and didn't find any constructive information

[Aleks]

As far as I know there isn't any normalisation and you have to post-process the values accordingly to the definition of 2D/1D "size" you choose.
The question I guess boils down to what volume (V) is used in the core of the transport distribution function, Ξ(E) (equation 14.4 in manual), but for that the developers would probably know best!
Cheers,
Aleks

[SilviaCasassa]

Dear Tarek,

the cell volume, used to normalize the transpor distribution function and the charge carrier concentration, for example, is compute as follows:
given the PARET matrix, which contains the cartesian coordinates of the lattice parameters,
1D: VOL = PARET(1,1)
2D: VOL = PARET(1,1)*PARET(2,2)-PARET(1,2)*PARET(2,1)

I hope I have understood your question, and I hope this helps you.
Silvia