Finding BandGap

[Anders Blom]

The ATK.KohnSham module is only relevant for version 2008.10.

In 10.8 you run "atkpython", not "atk".

[Anders Blom]

Well... it's different in 10.8. The contents of the module are available, but you don't need to import it. But the syntax is a little bit different, you can't just reuse the script from 2008.10.

[medeepak]

Hi

thanks for the reply
i computed density of states for the file i attached in one of my previous posts
all DOS values are zero
can you kindly tell me what might have been the problem
i am stuck at it for a long time now

[Anders Blom]

Please post the full complete script that you ran, as well as the log file.

[medeepak]

Hi
i have attache d my log and script file in this zip file

[Anders Blom]

The script attached is a molecule. You should compute the density of states for a periodic structure. Even if it technically is possible to do it for a molecule, I don't think the results will be what you are looking for.

[medeepak]

i calculated its molecular energy spectrum as well
but even in that i get straight lines parallel to x axis

[Anders Blom]

Of course, it's a molecule. All molecules have discrete spectra (sharp levels).

[medeepak]

Thanks for your replies

[medeepak]

Hi
 
i created a small distortion in graphene nanoribbon as given in the tutorial

http://www.quantumwise.com/documents/tutorials/BasicGrapheneTutorial/index.html/chap.zigzag_transport.html#id1286600

i want to find its band gap
since its a molecule i cannot run bandstructure calculations and as i understand from discussion even DOS will not give correct results
so how to do it?
kindly help

[Anders Blom]

If you follow the tutorial, it's a periodic structure, not a molecule. At some point you, by mistake, must be converting the structure to a molecule. Don't

[medeepak]

Hi

i corrected my mistake and plotted the bandstructure and density of states plot for the structure
the bandstrcuture consists of straight lines and in density of states there is a small peak near zero instead of discontinuity between HOMO and LUMO
what might have been the problem

i have attached my script file and log file with it

 

[Anders Blom]

The bands around the Fermi level are not flat. Results look ok.