Hi Roberto, Why do you use that huge smearing (3000K)? Are you sure you need it? Given the small gap, your system behaves like a metal right now. If I were you I would try to reduce it to let's say 30K so there are no more fractional occupations.
Marton -- PhD student Department of Atomic Physics Budapest University of Technology and Economics On Tue, Mar 8, 2011 at 11:45 AM, Roberto Guerra <[email protected]> wrote: > Hello, > > noone of the developers is interested in such a fundamental issue? It may > be a bug... > > RG > > > On Mon 07 Mar 2011, you wrote: >> Dear all, >> >> I repeated the calculation using a 2x2x2 grid (input file attached). The >> result is the same. This is not surprising, since the problem is not >> related, in my opinion, to the calculation accuracy (also, the >> calculation at the gamma point should be reasonable for an amorphous >> system). >> >> I verified that the Fermi energy lies inside the gap (bands attached). >> >> The epsimg is larger than zero at E<Egap. That's not possible. >> >> >> Roberto >> >> In date 5/3/11 23:52:32, Alexander Vozny wrote: >> > Roberto, >> > are you sure your Fermi level is in the gap? >> > If yes, then I would agree with Karim that most likely your k-grid for >> > DOS is different from k-grid for optical calculation. >> > Alexander. >> >> In date 4/3/11 18:40:44, karim rezouali wrote: >> > Roberto, >> > >> > The band structure appears not to be totally correct. Seeing your >> > input file systlab.fdf, I realized that this curve is obtained under >> > the gamma point.approximation >> > >> > Try to sample the Brillouin zone as follows: >> > %block kgrid_Monkhorst_Pack >> > 2 0 0 0.0 >> > 0 2 0 0.0 >> > 0 0 2 0.0 >> > %endblock kgrid_Monkhorst_Pack >> > >> > >> > Optical calculations: >> > >> > %block Optical.Mesh >> > >> > 2 2 2 >> > >> > %endblock Optical.Mesh >> > >> > These changes will make the calculation slightly heavier but that's >> > the price to pay for something more accurate. >
