Dear Eyvaz, You are right. I already mentioned this in my first post. In the right physical way I want to simulate doping by shifting the chemical potential to an energy near the original Fermi energy for the charge neutral, isolating system. In any case the chemical potential has to be shifted in either valence- or conduction band and therefore there would be an iso-energy surface (what I sloppy called Fermi surface...).
in any case, thank you Nicki > Dear Nicki, > >> I just want to know whether and how it is possible to shift >> the Fermi energy before constructing the Fermi surface?! > >> I just want to know whether and how it is possible to shift >> the Fermi energy before constructing the Fermi surface?! > > I should note there is NO Fermi level, thus, no Fermi surface for > semiconductors!!! Please think about why. > > Bests, > Eyvaz. > > ------------------------------------------------------------------- > Prof. Eyvaz Isaev, > Theoretical Physics Department, Moscow State Institute of Steel & > Alloys, Russia, > Department of Physics, Chemistry, and Biology (IFM), Linkoping > University, Sweden > Condensed Matter Theory Group, Uppsala University, Sweden > Eyvaz.Isaev at fysik.uu.se, isaev at ifm.liu.se, eyvaz_isaev at yahoo.com Dear Paolo, The previous stages are the formal ones: -making a proper scf calculation for the isolating system -calculate the total DOS to obtain the size of the gap and the possible energetic positions of valence/conduction band edge, where later on the chemical potential should be shifted into. -generating a k-point grid in the BZ with kvecs_FS.x -afterwards the eigenvalues are calculated on this grid for one special energy -> this is the Fermi energy, but: For my isolating system the Fermi energy would be in the gap, therefore there wont be an eigenvalue for given k-points at the Fermi energy. If I shift the energy to a value right where states are, then I would expect of course some contribution to an iso-energetic surface. But how to change this 'Fermi energy' in the right way. Is it enough to change the parameter in input_FS? Of course I know, that the system isn't charge-neutral anymore after artificially shifting the Fermi energy. Thanks a lot, Nicki > On Dec 23, 2009, at 14:32 , Nicki Frank Hinsche wrote: > >> plotting the fermi surface for the shifted energy would be the last >> stage... > > and what are the previous stages? P. > --- > Paolo Giannozzi, Dept of Physics, University of Udine > via delle Scienze 208, 33100 Udine, Italy > Phone +39-0432-558216, fax +39-0432-558222 ------------------------------------------------------------- Nicki Frank Hinsche, Dipl. Phys. Institut f?r Physik - Theoretische Physik, Martin-Luther-Universit?t Halle-Wittenberg, Von-Seckendorff-Platz 1, Raum 1.07 D-06120 Halle/Saale, Germany Tel.: ++49 345 5525460 nicki.hinsche at physik.uni-halle.de -------------------------------------------------------------
