Hi ???, The energy zero in any infinite system is arbitrary. In the lack of a surface, only energy differences matter. The zero-temperature Fermi energy of an insulator is also arbitrary, though usually assumed to lie at the middle of the gap.
Hope this helps. Meanwhile, would you mind signing your posts with your name and affiliation? Thanks — Stefano B > On 7 Aug 2018, at 09:17, 문태환 <[email protected]> wrote: > > Hello. I am a beginner to try DFT calculations using quantum espresso (GUI > BURAI) for the first time. > An attempt was made to calculate the SCF and pDOS using the CIF-file of the > organic-inorganic hybrid material (eg MAPbI3). I wanted to get the fermi > energy, but I could not find it in the output file of nscf, dos, pdos, scf, > etc. because I was immature and calculated occupation as 'fixed'. > The problem is that the energy of HOMO and LUMO is calculated as about 1.1 eV > and 4.4 eV, and I want to know what is the criterion of 0 eV. > > If I use the gaussian smearing method, can I get the correct fermi energy? > > _______________________________________________ > users mailing list > [email protected] <mailto:[email protected]> > https://lists.quantum-espresso.org/mailman/listinfo/users > <https://lists.quantum-espresso.org/mailman/listinfo/users> — Stefano Baroni - SISSA, Trieste - http://stefano.baroni.me, stefanobaroni (Skype) If the prediction that an airplane can stay up depends on the difference between Riemann and Lebesgue integration, I don’t want to fly in it [Richard W. Hammings]
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