Dear Mohaddeseh,

To perform linear response calculations (phonons, calculation of Hubbard 
parameters, etc.) for magnetic insulators, I use the procedure described in 
q-e/HP/examples/example02/README.


If you have a gapped system, you should not use smearing, because there can be 
numerical issues (due to the division by zero, because the DOS at the Fermi 
level can be very small using small smearing for insulators, see Eq. (79) in 
Rev. Mod. Phys. 73,  515 (2001)).


Greetings,

Iurii


--
Dr. Iurii Timrov
Postdoctoral Researcher
STI - IMX - THEOS and NCCR - MARVEL
Swiss Federal Institute of Technology Lausanne (EPFL)
CH-1015 Lausanne, Switzerland
+41 21 69 34 881
http://people.epfl.ch/265334
________________________________
From: users <[email protected]> on behalf of Mohad 
Abbasnejad <[email protected]>
Sent: Thursday, August 13, 2020 7:58:21 PM
To: [email protected]
Subject: [QE-users] Regarding "occupations" keyword in input file

Dear QE users,

Hello

I have a general question.
My structure is Mott hubbard and has a band gap of about 2 eV. It is also 
antiferromagnetic in its ground state.
I can obtain antiferromagnetic state and the desired band gap with hubbard 
parameters by both ways:
occupations: smearing
occupations: fixed
A) I am wondering whether these occupations can have effect on the phonon 
frequencies?
B) When is it preferable to use occupation fixed in our calculations?

Any help would be appreciated.
Thanks in advance.

Regards,
Mohaddeseh

--
---------------------------------------------------------
Mohaddeseh Abbasnejad,
Assistant Professor of Physics,
Faculty of Physics,
Shahid Bahonar University of Kerman,
Kerman, Iran
P.O. Box 76169-133
Tel: +98 34 31322199
Fax: +98 34 33257434
Cellphone: +98 917 731 7514
E-Mail:     
[email protected]<mailto:[email protected]>
Website:  
academicstaff.uk.ac.ir/moabbasnejad<http://academicstaff.uk.ac.ir/moabbasnejad>
---------------------------------------------------------

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