[Pw_forum] Problem in Bands of Graphene Nanoribbon

[Giovanni Cantele]

On Jul 2, 2012, at 1:24 PM, ÁÙ·çŪµÑ 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¨C3429.
Giovanni




--

**** PLEASE NOTICE THE NEW E-MAIL ADDRESS: giovanni.cantele at spin.cnr.it

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Scienze Fisiche
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: http://people.na.infn.it/~cantele
                     http://www.nanomat.unina.it

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20120702/e737875b/attachment.html>