[DFTB-Plus-User] Band Gap calculation

[Ben Hourahine]

Hello Sarah,

Thoughts so far:

1) Are you comparing equivalent k-points between the different codes?

2) What DFT functional are you using? DFTB functional tends to be
similar to GGA but with an overestimation of the gap in most cases (LDA
might be giving a smaller value).

3) Is there anything special about the electronic structure of this
system (flat band correlation effects in moiré graphene)?

Regards

Ben

On 04/11/18 10:58, Sarah Gamal wrote:
> This is the right file.
> Sorry for the disturbance.
>
> On Sun, Nov 4, 2018 at 12:56 PM Sarah Gamal <s.abouelhasab at gmail.com
> <mailto:s.abouelhasab at gmail.com>> wrote:
>
>     Dear,
>     I am working on a project and we need to calculate the band gap
>     for graphene nanomesh.
>     The band gap was calculated for the same system by siesta and
>     espresso and it was 0.7 eV.
>     When it's calculated by DFTB+ it was about 0.185 eV.
>
>     What do you think the problem?
>     I attached the input file, should I add any parameters?
>
>
>
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      Dr. B. Hourahine, SUPA, Department of Physics,
    University of Strathclyde, John Anderson Building,
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