[DFTB-Plus-User] Bandgap of GNR

[Gabriele Penazzi]

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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