Dear Mehmet and Hui Wang, That's what I did. From my calculations the occupied and unoccupied bands touch only at K point. I was just confused because the scf calculation does not output a zero gap. I mean the line "highest occupied, lowest unoccupied level" shows two different values and I expected them to be equal. So, it seems I did not too bad in fact. But how to experimentally get a zero gap then? Thanks,
Eric. On 03/09/2011 07:02 AM, Mehmet Topsakal wrote: > Dear Eric, > > In addition, if you select 18x18x1 kpoints, your mesh should include > both K and M points. > > But for a band-structure calculation, you should arrange a kpoints > list along special directions, such as from GAMMA-to-M-to-K-to-GAMMA, > and do a nscf calculation.... > > > > On Wed, Mar 9, 2011 at 11:28 AM, xirainbow <nkxirainbow at gmail.com > <mailto:nkxirainbow at gmail.com>> wrote: > > Dear Eric: > The occupied and unoccupied bands touch each other only at M > point(or K point, I forget it). > You must include this point in you k-mesh. > Furthermore, if you include spin-orbital coupling, the band gap > will be opened at this point. > > On Thu, Mar 10, 2011 at 1:30 AM, Eric Germaneau > <germaneau at gucas.ac.cn <mailto:germaneau at gucas.ac.cn>> wrote: > > Dear all, > > I'm trying to compute graphene's band gap but get stuck. > From my understanding a scf calculation should provide the > same energy for the highest occupied and lowest occupied level > which means a zero gap. > I played with the number a kpoints a finally got a band gap of > 0.57 which is not null. > The scf convergence looks good. > I'm not (yet) an expert in DFT calculation so may did > something wrong or misunderstood something here. > So, I wonder if someone has already successfully performed > such calculation. > I have attached my input file. > Thanks in advance, > > Eric. > > -- > /Be the change you wish to see in the world > / ? Mahatma Gandhi ? > > Dr. ?ric Germaneau <mailto:germaneau at gucas.ac.cn> > > College of Physical Sciences > Graduate University of Chinese Academy of Sciences > Yuquan Road 19A > Beijing 100049 > China > > /Please consider the environment before printing this email. > Consid?rez svp l'environnement avant d'imprimer cet email. / > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org <mailto:Pw_forum at pwscf.org> > http://www.democritos.it/mailman/listinfo/pw_forum > > > > > -- > ____________________________________ > Hui Wang > School of physics, Fudan University, Shanghai, China > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org <mailto:Pw_forum at pwscf.org> > http://www.democritos.it/mailman/listinfo/pw_forum > > > > > -- > > Mehmet Topsakal (Ph.D. Student) > UNAM-Institute of Materials Science and Nanotechnology. > Bilkent University. 06800 Bilkent, Ankara/Turkey > Tel: 0090 312 290 3527 ; Fax: 0090 312 266 4365 > http://www.researcherid.com/rid/A-5015-2010 > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum -- /Be the change you wish to see in the world / ? Mahatma Gandhi ? Dr. ?ric Germaneau <mailto:germaneau at gucas.ac.cn> College of Physical Sciences Graduate University of Chinese Academy of Sciences Yuquan Road 19A Beijing 100049 China /Please consider the environment before printing this email. Consid?rez svp l'environnement avant d'imprimer cet email. / -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110310/cee26e31/attachment.htm