[QE-users] How to obtain fermi energy through pDOS calculation of quantum espresso?

[문태환]

Dear Stefano,

Your advice has helped a lot.

If I can ask you one more question, can I calculate the fermi energy for semiconductor material if I use DOS calculations using 'gaussian smearing' instead of 'occupations = fixed'?

Thank you again.



Moon Taehwan, chung-ang university

________________________________
보낸 사람: Stefano Baroni <baroni at sissa.it> 대신 users <users-bounces at lists.quantum-espresso.org>
보낸 날짜: 2018년 8월 7일 화요일 오후 4:42:30
받는 사람: Quantum Espresso users Forum
제목: Re: [QE-users] How to obtain fermi energy through pDOS calculation of quantum espresso?

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 <th4512 at cau.ac.kr<mailto:th4512 at cau.ac.kr>> 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
users at lists.quantum-espresso.org<mailto:users at lists.quantum-espresso.org>
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]



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20180807/8168f042/attachment.html>