Dear Elie, The Fermi level in graphene converges very slowly with the k-point sampling. Did you check the result with a very large number of k-points?
Alexandra ----------------------------------------------------------- Alexandra Carvalho, Ceramics Laboratory Swiss Federal Institute of Technology of Lausanne (EPFL) Quoting Giovanni Cantele <giovanni.cantele at na.infn.it>: >> Dear all, >> I have plotted the density of states of graphene but when I looked at the >> graph, DOS was not zero at the fermi level (I got it to be -0.988 eV). my >> Programm seems pretty fine and i have checked it several times but with in >> vain..You will find attached the ps version and the input for the dos.x >> command... >> Regards >> Elie Moujaes >> University of Nottingham >> NG7 2RD >> UK > > The problem that the Fermi level is not at the energy you expect might not > be related to a mistake. The zero energy is not well defined in a > plane-wave calculation (try to browse the forum, there should be more than > one topic about that!). One should compute the DOS, then calculate the > Fermi energy (as the energy at which the integrated DOS matches the number > of the electrons), then for the sake of clarity you can shift you DOS (or > band structure) plot so as the Fermi energy is at 0. > > However, this might not be the problem in you calculation. > I'm not very sure that your calculation is right, because the shape of > your DOS plot does not look like the one of graphene. So the first problem > to solve is to understand on the top of which scf / nscf calculation you > have built your DOS plot. Unless I missed something, there are not > sufficient elements to understand what happened. > > Giovanni > > -- > Giovanni Cantele, PhD > CNR-SPIN and Dipartimento di Scienze Fisiche > Universita' di Napoli "Federico II" > Complesso Universitario M. S. Angelo - Ed. 6 > Via Cintia, I-80126, Napoli, Italy > Phone: +39 081 676910 - Fax: +39 081 676346 > Skype contact: giocan74 > > ResearcherID: http://www.researcherid.com/rid/A-1951-2009 > Web page: http://people.na.infn.it/~cantele > http://www.nanomat.unina.it > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- Alexandra Carvalho, Ceramics Laboratory Swiss Federal Institute of Technology of Lausanne (EPFL)
