On Wed, 24 Mar 2010 13:31:24 +0100, Gabriele Sclauzero <sclauzer at sissa.it> wrote: > the Fermi energy is printed only at the end of calculations for metals. > In the case of insulators it is not defined. You can take any energy in > the gap as reference value for > the DOS plot.
I would add a small note on this: if for an insulator, or an isolated system, you specify a number of bands larger than the strict minimum (nelec/2) than you will get in output the LUMO and HOMO level. If you instead use the minimum number of bands than you can still get the HOMO, but you have to get it yourself from the bands printout, which can be a bit annoying but does not require any specific skill. Nevertheless, those number are good for isolated systems, not for insulator. The reason is that for an insulator you will probably use reciprocal-space grid with a small number of kpoints, hence the real HOMO and the real LUMO may as well be in point which is not in the grid. In order to have more accurate values you can do an NSCF calculation with a few more bands and many more kpoints. regards -- Lorenzo Paulatto *** Note: my affiliation has changed! please send future correspondence to: <Lorenzo.Paulatto at impmc.upmc.fr> *** post-doc @ IMPMC/UPMC - Universit? Paris 6 phone: +33 (0)1 44 27 74 89 www: http://www-int.impmc.upmc.fr/~paulatto/ previously: phd student @ SISSA & DEMOCRITOS (Trieste) phone: +39 040 3787 511 www: http://people.sissa.it/~paulatto/
