<div dir="auto">Hello,<div dir="auto"><br></div><div dir="auto">I had the same question actually.</div><div dir="auto">I am also simulating the same AFM Mott insulator.</div><div dir="auto">For structural optimization I usually use occupation="smearing" and smearing="Gaussian".</div><div dir="auto">Is it the correct way or should I choose different options.</div><div dir="auto"><br></div><div dir="auto">And during DOS I use occupation="tetrahedra" with the relaxed calculation.</div><div dir="auto"><br></div><div dir="auto">Please guide me with this problem.</div><div dir="auto"><br></div><div dir="auto">Regards</div><div dir="auto">Yuvam Bhateja</div><div dir="auto">IIEST Shibpur</div><div dir="auto">India</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, 14 Aug 2020, 3:49 pm Matteo Cococcioni, <<a href="mailto:matteo.cococcioni@unipv.it">matteo.cococcioni@unipv.it</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>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).</div><div><br></div><div>Greetings,</div><div><br></div><div>Matteo</div><div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Il giorno gio 13 ago 2020 alle ore 20:11 Timrov Iurii <<a href="mailto:iurii.timrov@epfl.ch" target="_blank" rel="noreferrer">iurii.timrov@epfl.ch</a>> ha scritto:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<p>Dear <span>Mohaddeseh</span>,</p>
<p><br>
</p>
<p>To perform linear response calculations (phonons, calculation of Hubbard parameters, etc.) for magnetic insulators, I use the procedure described in
<span>q-e/HP/examples/example02</span>/README.</p>
<p><br>
</p>
<p>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)).</p>
<p><br>
</p>
<p>Greetings,</p>
<p>Iurii<br>
</p>
<p><br>
</p>
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<div id="m_1661455119911043618gmail-m_6651723430055874966divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> users <<a href="mailto:users-bounces@lists.quantum-espresso.org" target="_blank" rel="noreferrer">users-bounces@lists.quantum-espresso.org</a>> on behalf of Mohad Abbasnejad <<a href="mailto:mohaddeseh.abbasnejad@gmail.com" target="_blank" rel="noreferrer">mohaddeseh.abbasnejad@gmail.com</a>><br>
<b>Sent:</b> Thursday, August 13, 2020 7:58:21 PM<br>
<b>To:</b> <a href="mailto:users@lists.quantum-espresso.org" target="_blank" rel="noreferrer">users@lists.quantum-espresso.org</a><br>
<b>Subject:</b> [QE-users] Regarding "occupations" keyword in input file</font>
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<div>
<div dir="ltr">Dear QE users,
<div><br>
<div>Hello <br>
</div>
<div><br>
</div>
<div>I have a general question.<br>
My structure is Mott hubbard and has a band gap of about 2 eV. It is also antiferromagnetic in its ground state.<br>
I can obtain antiferromagnetic state and the desired band gap with hubbard parameters by both ways:<br>
occupations: smearing<br>
occupations: fixed<br>
A) I am wondering whether these occupations can have effect on the phonon frequencies?<br>
B) When is it preferable to use occupation fixed in our calculations?</div>
<div><br>
</div>
<div>Any help would be appreciated.</div>
<div>Thanks in advance.</div>
<div><br>
</div>
<div>Regards,</div>
<div>Mohaddeseh</div>
</div>
<div><br>
</div>
-- <br>
<div dir="ltr">---------------------------------------------------------<br>
Mohaddeseh Abbasnejad, <br>
Assistant Professor of Physics,<br>
Faculty of Physics, <br>
Shahid Bahonar University of Kerman,<br>
Kerman, Iran<br>
P.O. Box 76169-133<br>
Tel: +98 34 31322199<br>
Fax: +98 34 33257434<br>
Cellphone: +98 917 731 7514<br>
E-Mail: <a href="mailto:mohaddeseh.abbasnejad@gmail.com" target="_blank" rel="noreferrer">mohaddeseh.abbasnejad@gmail.com</a><br>
Website: <a href="http://academicstaff.uk.ac.ir/moabbasnejad" target="_blank" rel="noreferrer">academicstaff.uk.ac.ir/moabbasnejad</a>
<br>
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