[DFTB-Plus-User] Bandgap of GNR

[u3129004 at edu.gifu-u.ac.jp]

Dear Gabriele,

Thank you very much for your early reply. I have questions.

*Why I do not need k-points in x direction?
*I do not know the meaning you said "your structure seemed not optimized
".

In addition, I tried again,but the result is like an attached file. what 
is the cause that my result do not agree with your result? I also 
attached the input file.

Sincerely yours,
Kazuma 

----- Original Message -----
> Hi Kazuma,
> 
> you don't need k-points in x direction here. I've run your input with
> the supercell folding set to 1 in x direction (left 25 in y). I 
lowered
> the force tolerance to 1e-3 too (didn't want to wait too long) and I 
get
> 1.42 eV (detail of dos around gap attached). Your structure seemed not
> optimized but this should not be the problem, even if I run the input 
as
> it is with the geometry you sent but removing optimization I get
> something around 1.3 eV. Maybe you do some mistake when evaluating the 
gap.
> 
> Best
> Gabriele
> 
> 
> On 01/13/2016 10:04 AM, u3129004 at edu.gifu-u.ac.jp wrote:
> > Dear DFTB+ user,
> > 
> > I calculated Density of states of graphene nanoribbon (please refer 
to 
> > an attached file). But I am doubtful of this result. Because the 
bandgap 
> > is a lot different from other calculation results which are 
calculated 
> > by Tight Binding method and first principal calculation. I attached 
my 
> > input file for this calculation.
> > 
> > It would be very helpful if you could provide me any advice.
> > 
> > Thank you in advance,
> > Kazuma
> > ---------------------------------------------------
> > Kazuma KIHIRA
> > Environmental & Renewable Energy Systems Division
> > Graduate School of Engineering, Gifu University
> > E-mail:u3129004 at edu.gifu-u.ac.jp
> > ---------------------------------------------------
> > 
> > 
> > 
> > _______________________________________________
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> > 
> 
> -- 
> --
> Dr. Gabriele Penazzi
> BCCMS - University of Bremen
> 
> http://www.bccms.uni-bremen.de/
> http://sites.google.com/site/gabrielepenazzi/
> phone: +49 (0) 421 218 62337
> mobile: +49 (0) 151 19650383
>  
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