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QuantumATK => General Questions and Answers => Topic started by: perfetti on July 26, 2012, 21:59

Title: Band gap in metallic carbon nanotube
Post by: perfetti on July 26, 2012, 21:59

Dear every one,
       I am calculating the bandstructure of cnt(5,5), and it should be very easy. However, I always got a small bandgap near Fermi level in the bandstructure.
       I used k point =30,  50, 100, and it doesn't change much. I keep using GGA, PBE,  since I've no idea how I should set up about other exchange-correlation function.
      My input script and the bandstructure are attatched. Any advice should be appreciated.  I just want to eliminate this gap, or at least understand it.
      Thank you!

Title: Re: Band gap in metallic carbon nanotube
Post by: Anders Blom on July 27, 2012, 00:41

Increase number of points on the band structure to 100. With just 20 points you don't hit the precise point where the gap is zero.