QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: serhan on July 19, 2009, 21:10

Title: Density of states
Post by: serhan on July 19, 2009, 21:10

I'd like to ask how can we calculate the density of states and plot it for carbon nanotubes in ATK? We have *.nc files of the simulations of various metallic CNTs (two-probe simulations). How can we extract DOS from these *.nc files?

Cheers,
Serhan

Title: Re: Density of states
Post by: zh on July 20, 2009, 02:58

To know how to calculate the DOS using ATK, you may refer to the tutorials demonstrated here:
http://quantumwise.com/tutorials (http://quantumwise.com/tutorials)
http://quantumwise.com/documents/tutorials/bulk_dos.py (http://quantumwise.com/documents/tutorials/bulk_dos.py)

The data for DOS is not stored in the '.nc' files, so they can not be extracted. You may use "ncdump" tool of NetCDF to see what are stored in the '.nc' file.

Title: Re: Density of states
Post by: serhan on July 20, 2009, 05:31

Hi,

Thanks for your reply. However, the tutorial writes: "The method used for the DOS calculation is the tetrahedron method, suitable for real
3D crystal. The provided script is, as the name indicates, not suitable for 1D or 2D systems like nanotubes or graphene."

We need to calculate the DOS of CNT, a 1-D structure.

Also, the tutorial has an example:

Code

from ATK.KohnSham import *
from bulk_dos import *
# Specify checkpoint file here!
scf = restoreSelfConsistentCalculation('c:/vnl/au.nc')
dos = calculateDensityOfStates(scf, -5*eV, 5*eV, 100, accuracy=4)
dos.plot('c:/vnl/au_dos.png')

From this I understand that the DOS can be extracted from scf included in *.nc files.

Cheers,
Serhan

Title: Re: Density of states
Post by: zh on July 20, 2009, 08:46

For the DOS calculations, it has been discussed many times in this forum, e.g., see the topic here:
http://quantumwise.com/forum/index.php?topic=261.0 (http://quantumwise.com/forum/index.php?topic=261.0)

Title: Re: Density of states
Post by: serhan on July 20, 2009, 09:03

Thanks, it's now Ok.

Cheers
Serhan