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<p>Dear Iurii and Mahmoud,</p>
<p><br>
</p>
<p>Thank you for your response. I have a follow-up question regarding the impact of using different Hubbard U values in the initial SCF calculation. Specifically, how does the change of U value in the first scf calculation (e.g. from 0.001 eV changes to 5 eV)
impact the simplified Wannier functions calculation? <br>
</p>
<p><br>
</p>
<p>I appreciate your insights on these points.</p>
<p><br>
</p>
<p>Best regards, <br>
</p>
<p>Yin-Ying Ting <br>
</p>
<p>PhD Student in Forschungszentrum Jülich</p>
<p><br>
</p>
<p></p>
<div class="moz-cite-prefix">On 26.01.24 10:16, Timrov Iurii wrote:<br>
</div>
<blockquote type="cite" cite="mid:ZR0P278MB02669AB9398776A148060A38EE792@ZR0P278MB0266.CHEP278.PROD.OUTLOOK.COM">
<style type="text/css" style="display:none;">P {margin-top:0;margin-bottom:0;}</style>
<div class="elementToProof"><span style="letter-spacing: normal; font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(36, 36, 36); background-color: rgb(255, 255, 255); font-weight: 400;">Dear
Yin-Ying,</span></div>
<div class="elementToProof"><span style="letter-spacing: normal; font-family: "Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif; font-size: 14.666667px; color: rgb(36, 36, 36); background-color: rgb(255, 255, 255); font-weight: 400;"><br>
</span></div>
<div class="elementToProof"><span style="letter-spacing: normal; font-family: "Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif; font-size: 14.666667px; color: rgb(36, 36, 36); background-color: rgb(255, 255, 255); font-weight: 400;">> Why
is it not recommended or feasible to employ the Hubbard U parameters right from the first SCF calculation?</span></div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
It is feasible, you can do that. QE contains just one example with starting U=0.001, but you can use any value. </div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof"><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">The
</span><span style="letter-spacing: normal; font-family: "Segoe UI", "Segoe UI Web (West European)", "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, "Helvetica Neue", sans-serif; font-size: 14.666667px; color: rgb(36, 36, 36); background-color: rgb(255, 255, 255); font-weight: 400;">pmw.x</span><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"> codes
reads the Kohn-Sham wavefunctions (which can be DFT or DFT+U), and then builds Wannier functions. Note that these are not maximally localized. In the future releases of QE there will be a possibility to use maximally localized Wannier functions from Wannier90
for DFT+U calculations (we are working on that).</span></div>
<div class="elementToProof"><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><br>
</span></div>
<div class="elementToProof"><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">HTH</span></div>
<div class="elementToProof"><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><br>
</span></div>
<div class="elementToProof"><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">Iurii </span></div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div id="Signature">
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(102, 102, 102);">----------------------------------------------------------</span></div>
<div><span style="font-family: Cambria, Georgia, serif; font-size: 12pt; color: rgb(102, 102, 102);">Dr. Iurii TIMROV</span></div>
<div><span style="font-family: Cambria, Georgia, serif; font-size: 12pt; color: rgb(102, 102, 102);">Tenure-track scientist</span></div>
<div><span style="font-family: Cambria, Georgia, serif; font-size: 12pt; color: rgb(102, 102, 102);">Laboratory for Materials Simulations (LMS)</span></div>
<div><span style="font-family: Cambria, Georgia, serif; font-size: 12pt; color: rgb(102, 102, 102);">Paul Scherrer Institut (PSI)</span></div>
<div><span style="font-family: Cambria, Georgia, serif; font-size: 12pt; color: rgb(102, 102, 102);">CH-5232 Villigen, Switzerland</span></div>
<div><span style="font-family: Cambria, Georgia, serif; font-size: 12pt; color: rgb(102, 102, 102);">+41 56 310 62 14</span></div>
<div><span style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);"><a href="https://www.psi.ch/en/lms/people/iurii-timrov" target="_blank" rel="noopener noreferrer" data-auth="NotApplicable" data-linkindex="0" moz-do-not-send="true" class="moz-txt-link-freetext">https://www.psi.ch/en/lms/people/iurii-timrov</a></span></div>
</div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> users
<a class="moz-txt-link-rfc2396E" href="mailto:users-bounces@lists.quantum-espresso.org">
<users-bounces@lists.quantum-espresso.org></a> on behalf of Yin-Ying Ting <a class="moz-txt-link-rfc2396E" href="mailto:y.ting@fz-juelich.de">
<y.ting@fz-juelich.de></a><br>
<b>Sent:</b> Wednesday, January 24, 2024 17:09<br>
<b>To:</b> <a class="moz-txt-link-abbreviated" href="mailto:users@lists.quantum-espresso.org">
users@lists.quantum-espresso.org</a> <a class="moz-txt-link-rfc2396E" href="mailto:users@lists.quantum-espresso.org">
<users@lists.quantum-espresso.org></a><br>
<b>Subject:</b> [QE-users] Hubbard U Parameters in pmw.x</font>
<div> </div>
</div>
<div class="BodyFragment"><font size="2"><span style="font-size:11pt;">
<div class="PlainText">Dear Quantum Espresso Community,<br>
<br>
I am currently working with the poormanwannier.x (pmw.x) as demonstrated<br>
in example05 of PP. In this example, the procedure begins with a<br>
self-consistent field (SCF) calculation without the incorporation of<br>
Wannier functions (wf) and with very small Hubbard parameters (around<br>
0.001). This is followed by the execution of pmw.x and a subsequent<br>
second SCF calculation, this time including Wannier functions and the<br>
Hubbard U parameters.<br>
<br>
My question pertains to the rationale behind this two-step SCF<br>
calculation approach, particularly concerning the Hubbard U parameters.<br>
Why is it not recommended or feasible to employ the Hubbard U parameters<br>
right from the first SCF calculation? Understanding the underlying<br>
reasoning for this process would greatly enhance my comprehension of the<br>
method and its applications.<br>
<br>
I appreciate any insights or explanations you can provide. Thank you for<br>
your time and assistance.<br>
<br>
Best regards,<br>
<br>
PhD student in Forschungszentrum Jülich<br>
<br>
Yin-Ying Ting<br>
<br>
--<br>
<br>
Forschungszentrum Jülich GmbH<br>
Institute of Energy and Climate Research<br>
Theory and Computation of Energy Materials (IEK-13)<br>
E-mail: <a class="moz-txt-link-abbreviated" href="mailto:y.ting@fz-juelich.de">y.ting@fz-juelich.de</a><br>
<br>
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<pre class="moz-quote-pre" wrap="">_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (<a class="moz-txt-link-abbreviated" href="http://www.max-centre.eu">www.max-centre.eu</a>)
users mailing list <a class="moz-txt-link-abbreviated" href="mailto:users@lists.quantum-espresso.org">users@lists.quantum-espresso.org</a>
<a class="moz-txt-link-freetext" href="https://lists.quantum-espresso.org/mailman/listinfo/users">https://lists.quantum-espresso.org/mailman/listinfo/users</a></pre>
</blockquote>
<div class="moz-signature">-- <br>
<p>Forschungszentrum Jülich GmbH<br>
Institute of Energy and Climate Research<br>
Theory and Computation of Energy Materials (IEK-13)<br>
E-mail: <a href="mailto:y.ting@fz-juelich.de" class="moz-txt-link-freetext">y.ting@fz-juelich.de</a>
</p>
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Sitz der Gesellschaft: Jülich<br>
Eingetragen im Handelsregister des Amtsgerichts Düren Nr. HR B 3498<br>
Vorsitzender des Aufsichtsrats: MinDir Stefan Müller<br>
Geschäftsführung: Prof. Dr. Astrid Lambrecht (Vorsitzende),<br>
Karsten Beneke (stellv. Vorsitzender), Dr. Ir. Pieter Jansens<br>
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