Hello, I had the same question actually. I am also simulating the same AFM Mott insulator. For structural optimization I usually use occupation="smearing" and smearing="Gaussian". Is it the correct way or should I choose different options.
And during DOS I use occupation="tetrahedra" with the relaxed calculation. Please guide me with this problem. Regards Yuvam Bhateja IIEST Shibpur India On Fri, 14 Aug 2020, 3:49 pm Matteo Cococcioni, <[email protected]> wrote: > In addition to what Iurii says, if you use occupation="smearing" the > phonon code will assume your system is metallic and will never compute the > dielectric tensor and Born effective charge which you need, instead to get > the LO-TO splittings at Gamma (non analytic part of the dynamical matrix). > > Greetings, > > Matteo > > > Il giorno gio 13 ago 2020 alle ore 20:11 Timrov Iurii < > [email protected]> ha scritto: > >> 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] >> Website: academicstaff.uk.ac.ir/moabbasnejad >> --------------------------------------------------------- >> >> _______________________________________________ >> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) >> users mailing list [email protected] >> https://lists.quantum-espresso.org/mailman/listinfo/users > > > > -- > Matteo Cococcioni > Department of Physics > University of Pavia > Via Bassi 6, I-27100 Pavia, Italy > tel +39-0382-987485 > e-mail [email protected] <[email protected]> > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
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