Just one more comment. For hexagonal systems it is usually required to do not apply a shift for the k-mesh and to include the gamma point in the DOS calculation. In your case, I will check the convergency of you DOS calculation with and without a shift of the k-mesh. It is highly probable that the band gap is only defined for high-symmetry k-points, explaining the difference between the DOS and the band structure (the latter one based on high-symmetry points).
Regards Xavier On 04/08/2012 09:45 AM, arqum hashmi wrote: > Thanks Sir Xavier > i will do it then tell you. > Best Regards > Arqum Hashmi > > *From:* Rocquefelte <Xavier.Rocquefelte at cnrs-imn.fr> > *To:* A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at> > *Sent:* Sunday, April 8, 2012 4:41 PM > *Subject:* Re: [Wien] help required > > For the convergency of the DOS you simply have to plot the DOS for > different k-meshes (increasing progressively the number of k-points) > and when the DOS stops to evolve then you are converged. > > Regards > > Xavier > > > On 04/07/2012 03:29 PM, arqum hashmi wrote: >> Thanks a lot sir Xavier, >> Before this i also thinked about this that i don't have denser k >> mesh thats why i didn't get correct results. >> yeah thats why i am saying to you that band structure giving very >> unnatural behaviour. Sorry not ferromagnetic you can say that >> conductor behaviour because band lines crossing fermi level. >> opposite behaviour means DOS showing bandgap but band structure >> showing conducting behaviour. >> how can i check the convergency of my DOS calculation. >> i am really worried about this. >> Best Regards >> Arqum Hashmi >> >> *From:* Rocquefelte <Xavier.Rocquefelte at cnrs-imn.fr> >> <mailto:Xavier.Rocquefelte at cnrs-imn.fr> >> *To:* A Mailing list for WIEN2k users >> <wien at zeus.theochem.tuwien.ac.at> >> <mailto:wien at zeus.theochem.tuwien.ac.at> >> *Sent:* Saturday, April 7, 2012 8:48 PM >> *Subject:* Re: [Wien] help required >> >> I have difficulties to follow your arguments. In your first email you >> have mentioned that you did non spin polarized calculations, and now >> you are speaking about ferromagnetic character at M point! >> >> In addition, I do not understand the following line: "DOS and band >> structre showing totally opposite behaviour". >> >> My feeling remains the same and particularly in the present case. You >> are looking at graphene, a 2D system for which the band dispersion is >> large. >> You must see Van't Hoff singularities in the DOS and you need to have >> a dense k-mesh to have a well-converged DOS. >> Did you check the convergency of your DOS calculation but using >> denser k-meshes? >> >> Regards >> >> Xavier >> >> >> >> >> On 04/07/2012 12:45 PM, arqum hashmi wrote: >>> Thanks Sir Xavier, >>> but the problem is this that both DOS and band structre showing >>> totally opposite behaviour. >>> my system is graphene with some doping of Boron nitride. >>> DOS is good as we expect but band structure shows really strange >>> behaviour. graphene has zero bandgap in brillioun zone at K point >>> and when i used graphene with BN, we obtain some ferromagnetic at M >>> point when we plot band structure. >>> i don't know whats wrong with band structure. >>> Best Regrads >>> Arqum Hashmi >>> >>> *From:* Rocquefelte <Xavier.Rocquefelte at cnrs-imn.fr> >>> <mailto:Xavier.Rocquefelte at cnrs-imn.fr> >>> *To:* A Mailing list for WIEN2k users >>> <wien at zeus.theochem.tuwien.ac.at> >>> <mailto:wien at zeus.theochem.tuwien.ac.at> >>> *Sent:* Saturday, April 7, 2012 7:02 PM >>> *Subject:* Re: [Wien] help required >>> >>> The band gap estimated from the DOS is always larger than the one >>> extracted from the band structure (which is more accurate). >>> To estimate the fundamental band gap you should consider the one >>> deduced from the band structure. >>> >>> The difference you observed is certainly due to the existence of a >>> broad band which has a very low density near the Fermi energy. As a >>> consequence, you can have the feeling that you have a gap by looking >>> at the DOS. >>> >>> Could you give more details about your calculations ? Which system ? >>> The value of the band gap from the DOS ? >>> >>> Regards >>> >>> Xavier >>> >>> >>> On 04/07/2012 07:41 AM, arqum hashmi wrote: >>>> Dear Wien2k Users >>>> >>>> I am doing non spin polarized calculation. In this calculation, DOS >>>> and Band structure are not consistent with each other. DOS shows >>>> that it has some band gap but in band structure it shows that it is >>>> metallic. I don't know what is the problem in this and why DOS and >>>> Band structure is inconsistent with each other. >>>> i expect that DOS is correct but something is wrong with band >>>> structure. >>>> If any one of you give any suggestion that how i can solve this >>>> problem. I will be very thankful to you. >>>> >>>> Best Regards >>>> Arqum Hashmi >>>> >>>> >>>> _______________________________________________ >>>> Wien mailing list >>>> Wien at zeus.theochem.tuwien.ac.at <mailto:Wien at >>>> zeus.theochem.tuwien.ac.at> >>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >>> >>> >>> _______________________________________________ >>> Wien mailing list >>> Wien at zeus.theochem.tuwien.ac.at <mailto:Wien at >>> zeus.theochem.tuwien.ac.at> >>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >>> >>> >>> >>> _______________________________________________ >>> Wien mailing list >>> Wien at zeus.theochem.tuwien.ac.at <mailto:Wien at >>> zeus.theochem.tuwien.ac.at> >>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >> >> >> _______________________________________________ >> Wien mailing list >> Wien at zeus.theochem.tuwien.ac.at <mailto:Wien at >> zeus.theochem.tuwien.ac.at> >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >> >> >> >> _______________________________________________ >> Wien mailing list >> Wien at zeus.theochem.tuwien.ac.at <mailto:Wien at >> zeus.theochem.tuwien.ac.at> >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > > > _______________________________________________ > Wien mailing list > Wien at zeus.theochem.tuwien.ac.at <mailto:Wien at zeus.theochem.tuwien.ac.at> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > > > > _______________________________________________ > Wien mailing list > Wien at zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20120408/8ea9ea95/attachment-0001.htm>
