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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.zFbpBTCl.DZ1v8KW1@infim.ro" alt=""></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" 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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