[Pw_forum] (no subject)

[Lorenzo Paulatto]

On Tuesday, December 01, 2015 08:02:12 AM Tariq Sami wrote:
> Dear all,     I have a (very basic) question regarding band structure
> calculations. One requires Fermi energy for band structure calculations but
> the are two different Fermi energies in thescf and nscf outputs. Can anyone
> please tell which one should i use and what's the basic difference?Thanks
> in advance

Dear Tariq,
it is the Fermi energy from the scf calculations that makes sense, especially 
if the band calculation was not performed over a regular grid. This is because 
the Fermi energy fixed by the condition of having a certain number of 
electrons, and the condition can only be enforced properly if the k=points 
form a suitable grid for integrating the Brillouin zone.

I think that if you use calculation="bands" instead of calculation="nscf" the 
Fermi energy should not be printed on output at all, but I may be wrong.

kind regards


-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
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