[Pw_forum] Problem in Bands of Graphene Nanoribbon

[Martin Gmitra]

Hi!
Such "crowded" bands one sees also for film calculations. Comparing
to 2D codes (e.g. FLEUR) I have seen that increasing vacuum clears
the "crowded" high energy states.

Martin Gmitra

Spintronics group
Uni Regensburg, Germany


On Mon, Jul 2, 2012 at 2:52 PM, Giovanni Cantele
<giovanni.cantele at spin.cnr.it> wrote:
>
> On Jul 2, 2012, at 1:24 PM, 临风弄笛 wrote:
>
> Hi! All
> I'm trying to calculate the quantum conductance of quasi one dimension
> structure with Wannier90 and PWscf.
> But the one dimension band structure of suppercell is weird: bands with high
> energy seem very "crowded".
> I meet this problem when calculating Al nanowire and graphene nanoribbon. It
> seems a computation error as
> energy seems to be limitted in a small range.
> I have raised the value of cutoff and distance between nanoribbons in
> directions perpendicular to transport,
> but results changed little.
> My friend plots the bands of graphene nanoribbon with fplo, which can be a
> reference I think.
>
> The input files and bands are in attachment.
>
> Thank you very much!
> <nscf.in><scf.in><bands.jpg><bands_fplo.jpg>_______________________________________________
>
>
> It seems that your band structure is correct. If you want to look at higher
> energy bands, due to the presence of
> these "free-electron-like" states, you must increase nbnd.
>
> The Wannier90 procedure might be useful to single out bands with a specific
> atomic character
> (e.g. those deriving from the pz orbitals of C atoms). See, as an example,
> Fig. 2 of Nano Lett., 2009, 9 (10), pp 3425–3429.
> Giovanni
>
>
>
>
> --
>
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>
> Giovanni Cantele, PhD
> CNR-SPIN
> c/o Dipartimento di Scienze Fisiche
> Universita' di Napoli "Federico II"
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