[Pw_forum] Evaluation of metallic/non-metallic conduction in carbon nanotubes

[Steven Kirk]

Hello,

I want to conduct a set of calculations on carbon nanotubes of different 
diameters and chiralities to establish:

1. If they are metallic, i.e. conducting, along the nanotube length
2. If they are not metallic, evaluating the band gap

Do I need to do an PW 'scf' run followed by a PW 'nscf' run? What 
smearing/occupancy parameters do I need to set (suggested values 
welcome) ? I have not spotted a clear output of the calculated band gap 
anywhere in PW's output files, so how can I calculate the band gap from 
the data given ?

Many thanks in advance,
Steve Kirk
-- 
Dr. Steven R. Kirk          <Steven.Kirk at htu.se, S.R.Kirk at physics.org>
Dept. of Computer Science, TMD               http://taconet.webhop.org
Univ. of Trollhattan/Uddevalla   Ph: +46 520 475318 Fax:+46 520 475399
P.O. Box 957 Trollhattan 461 29 SWEDEN