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<p>I also tried centering the slab around z=0 and now I am even more
confused. In the attached picture, the Hartree potential has
basically changed sign. What is the proper way to use the
assume_isolated=2D method?</p>
<p>Best regards,<br>
</p>
<p>Lucian<br>
</p>
<div class="moz-cite-prefix">On 25-Jun-24 8:14 AM, Lorenzo Paulatto
wrote:<br>
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cite="mid:83dd85df-0b85-4fe3-aa92-0465c27f8168@cnrs.fr">
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<p>Hello Lucian,</p>
<p>is the slab in the center of the cell, or around z=0 ?</p>
<p>Anyway, the option assume_isolated='2D' modifies the Hartree
interaction, adding a cut-off smooth step function at half the
cell z-length, i.e. 1/r → step(z)/r. If a long-range 1/r^n
propagates outward from your slab, at half the cell distance you
will see the step function. As long as this happens in a region
where there is vacuum, it is not a problem.</p>
<p>kind regards<br>
</p>
<div class="moz-cite-prefix">On 24/06/2024 13:09, Lucian D. Filip
wrote:<br>
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cite="mid:ff22e1ab-c597-4e93-b5ab-82e4990e8266@infim.ro">
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<p>Hello,</p>
<p>I am looking at a PbTiO3 slab in vacuum. The slab is in a
polarized state and I am trying to obtain the Hartree
potential with the dipole correction applied. I have seen that
the assumed_isolated = '2D' option should do just that.
However, I do not understand the result I am getting. In the
attached picture I have plotted the Hartree potential averaged
along the z axis, for the polarized state and the
centro-simmetric state with polarization zero.</p>
<p>The slab is 5 PTO unit cells thick and there are 20 Angstroms
of vacuum on each side. The vacuum region is well above the
requirements of assume_isolated ='2D'. Can anyone explain two
things:</p>
<p>1) why are there two regions in vacuum looking like a
staircase.</p>
<p>2) why is there an electric field still present?</p>
<p><br>
</p>
<p>The weird artefacts at the edges of the supercell are due to
the averaging procedure (i am still working on it, not sure
where it is coming from).</p>
<p><br>
</p>
<p>Best regards,</p>
<p>Lucian<br>
</p>
<p><br>
</p>
<p><img src="cid:part1.A11uyVv0.0u4WdG9q@infim.ro" alt=""
class=""></p>
<pre class="moz-signature" cols="72">--
Dr. Lucian Dragos Filip
National Institute of Materials Physics
Atomistilor str. 405A, PO Box MG. 7
Magurele, 077125
Bucharest, Romania
E-mail: <a class="moz-txt-link-abbreviated moz-txt-link-freetext"
href="mailto:lucian.filip@infim.ro" moz-do-not-send="true">lucian.filip@infim.ro</a>
Website: <a class="moz-txt-link-freetext"
href="https://lucianfilip.wordpress.com/" moz-do-not-send="true">https://lucianfilip.wordpress.com/</a></pre>
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<div class="moz-signature">-- <br>
<small>Dr. Lorenzo Paulatto<br>
IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université<br>
phone: +33 (0)1 442 79822 / skype: paulatz<br>
<a href="http://www.impmc.upmc.fr/~paulatto/"
class="moz-txt-link-freetext" moz-do-not-send="true">http://www.impmc.upmc.fr/~paulatto/</a>
- <a href="https://anharmonic.github.io/"
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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>
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</blockquote>
<pre class="moz-signature" cols="72">--
Dr. Lucian Dragos Filip
National Institute of Materials Physics
Atomistilor str. 405A, PO Box MG. 7
Magurele, 077125
Bucharest, Romania
E-mail: <a class="moz-txt-link-abbreviated" href="mailto:lucian.filip@infim.ro">lucian.filip@infim.ro</a>
Website: <a class="moz-txt-link-freetext" href="https://lucianfilip.wordpress.com/">https://lucianfilip.wordpress.com/</a></pre>
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