QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Arya on December 14, 2013, 21:29

Title: MOS2 bandstructure
Post by: Arya on December 14, 2013, 21:29

Hi All,

I am not able to reproduce the bandstructure of MOS2 monolayer. I am using
http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1894&context=nanopub
as reference band structure.

Below is the procedure I am following:
1. Select molybdenite delete 3 atoms on right.
2. Fit the unit cell
3. Go to lattice parameter and change lattice type to hexagonal.
4. Slater-Koster -> k space sampling = 1,3,3
5. Brillioun zone path K,G,M

Please have a look at attached image.

Thanks,
_Arya

Title: Re: MOS2 bandstructure
Post by: ramkrishna on December 15, 2013, 00:17

please check this... http://quantumwise.com/publications/tutorials/mini-tutorials/167

Title: Re: MOS2 bandstructure
Post by: Arya on December 15, 2013, 03:41

Just a question, is it always necessary to have an orthorhombic unitcell for bandstructure calculation? Why do we prefer orthorhombic cell?

Also the unit cell that I was using (mentioned in above comment of mine), what is wrong with that? For orthorhombic cell we do not get 'K point ' in Brillioun zone route as far as I know.


 
Thanks,
-Arya

Title: Re: MOS2 bandstructure
Post by: ramkrishna on December 15, 2013, 06:03

It is not necessary to choose orthorhombic cell to calculate bandstructure rather hexagonal cell will give you what you are trying to calculate. You can choose that for some particular situations, and that depends on what you want to calculate :) The procedure to calculate hexagonal MoS2 is more or less same as Graphene however, you have to be careful about the parameters.

Which version of ATK are you using? There was an error in the coordinates in the previous version. I think, it has been fixed in the current version. Please see http://quantumwise.com/forum/index.php?topic=2339.0#.Uq1DtPRDvBY

  

Title: Re: MOS2 bandstructure
Post by: Arya on December 15, 2013, 16:01

I am using 13.8. I don't see the reason why am I not getting correct results. As far as parameters are concerned all we need to chose is k space sampling (which is 1,3,3 for me for Slater Koster) and Brillioun zone route.

The problem is I want to know how to decide what parameters etc to use so that if I wish to calculate bandstruture for a new material I shouldn't rely on tutorials.

Thanks,
-Arya

Title: Re: MOS2 bandstructure
Post by: Shinji Usui on December 16, 2013, 07:59

I tried the calculation and could reproduce the bandstructure in the paper.
I used LDA instead of Slater-Koster.

Title: Re: MOS2 bandstructure
Post by: Anders Blom on December 16, 2013, 09:12

Quote from: Arya on December 15, 2013, 16:01

k space sampling (which is 1,3,3 for me for Slater Koster)

That's perhaps your main problem (besides the fact that I don't think there is any good Slater-Koster in ATK for MoS2). A more relevant choice, provided your layer is in the XY plane as usual, would be (27,27,1).

Title: Re: MOS2 bandstructure
Post by: Arya on December 16, 2013, 13:28

Thanks Dr Anders and Shinji Usui, I will try your script.

-Arya