[QE-developers] Matrix Elements of the Momentum Operator

[Paolo Giannozzi]

Thank you for reporting this. As far as I know, during a band calculation
the Fermi energy is not computed. It is however read from file (the one
produced by the previous scf calculation) and re-written to file at the end
of the band calculation. A zero (not set) Fermi energy means that it wasn't
computed during the scf calculation. This happens if you do not use
smearing.

There was however a bug with units: Ef was written to file in Hartree a.u.
but not converted to Rydberg a.u. when read. This was fixed a few days ago.

Paolo



On Thu, Jan 23, 2020 at 7:30 AM Rafal Korlacki <rkorlacki2 at unl.edu> wrote:

> Hello,
>
>
>
> I believe there is a bug in the routine write_p_avg in all the versions 6
> of QE. Specifically, in the following fragment:
>
>
>
>      !
>
>      !   Compute the number of occupated bands at this k point
>
>      !
>
>      DO ibnd = 1, nbnd
>
>         IF (et (ibnd, ik)<=ef) nbnd_occ = ibnd
>
>      ENDDO
>
>
>
> It seems that the variable ef=0 rather than whatever the right number is,
> and the code gets confused about which bands are occupied and which are
> not. If I replace ef with a number corresponding to an energy somewhere
> within the bandgap for a particular material, the output is consistent with
> earlier versions of QE, like 5.3.0. Otherwise the code calculates overlaps
> between the wrong band pairs, the format of the output varies between
> k-points, etc. I tested this behavior for QE 6.2 to 6.5.
>
>
>
> Best regards,
>
>
>
> Rafal Korlacki
>
> University of Nebraska-Lincoln
>
>
>
>
>
>
>
>
>
>
>
>
> _______________________________________________
> developers mailing list
> developers at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/developers
>


-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/developers/attachments/20200123/b7cdfd1d/attachment.html>