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<p>Hello <br>
</p>
<p>In any case, just to post it in this thread. <br>
</p>
<p>Fractional charge H pseudos for PZ-LDA can be found at this
page: <br>
</p>
<p><a class="moz-txt-link-freetext" href="http://www.quantum-espresso.org/pseudopotentials/original-qe-pp-library/h">http://www.quantum-espresso.org/pseudopotentials/original-qe-pp-library/h</a></p>
<p>they have names like <a class="element_anchor" target="_blank"
href="http://www.quantum-espresso.org/upf_files/H.pz-vbc_050.UPF">H.pz-vbc_050.UPF</a>
and analogous. </p>
<p>have a nice day <br>
</p>
<p>Pietro <br>
</p>
<p><br>
</p>
<p><br>
</p>
<br>
<div class="moz-cite-prefix">On 08/08/2018 16:39, Matthieu
Fortin-Deschênes wrote:<br>
</div>
<blockquote type="cite"
cite="mid:20180808143928.Horde.zVMmZeSJCjqiDxkjPhrF7DG@www.imp.polymtl.ca">Thanks
for the info. I'll take a look at those papers.
<br>
<br>
Matthieu
<br>
<br>
Giuseppe Mattioli <a class="moz-txt-link-rfc2396E" href="mailto:giuseppe.mattioli@ism.cnr.it"><giuseppe.mattioli@ism.cnr.it></a> a écrit :
<br>
<br>
<blockquote type="cite">
<blockquote type="cite">I believe fractional charge H atoms
would not be useful for these kinds of materials. Right?
<br>
</blockquote>
<br>
I suppose you are right. I can only suggest you to double check
the results and to carefully compare with experimental results
obtained on real systems. I cited C-diamond, which is "akin" to
Si and Ge, because surface hydrogenation induce a large upward
shift of both valence and conduction bands, measured by ARPES
and compared with DFT calculations here: Phys. Rev. B 94, 045307
(2016)
<br>
<br>
Surface or interstitial H is a well known dopant in
semiconductors. Among tons of papers (I'm ashamed to cite mine
:-)) I can suggest the classical Van de Walle Nature paper on
universal alignment of H (Nature 423, 626, 2003)
<br>
<br>
HTH
<br>
Giuseppe
<br>
<br>
Quoting Matthieu Fortin-Deschênes
<a class="moz-txt-link-rfc2396E" href="mailto:matthieu.fortin-deschenes@polymtl.ca"><matthieu.fortin-deschenes@polymtl.ca></a>:
<br>
<br>
<blockquote type="cite">Thanks Giuseppe,
<br>
<br>
I actually want to passivate the bottom of Si and Ge surfaces,
as well as one edge of a 2D nanoribbon (antimonene).
<br>
I believe fractional charge H atoms would not be useful for
these kinds of materials. Right?
<br>
<br>
I was not aware of this strong dopant effect, but I'd be
interested in reading more about it if you have any reference
to suggest.
<br>
<br>
Thank you,
<br>
<br>
Matthieu
<br>
<br>
Giuseppe Mattioli <a class="moz-txt-link-rfc2396E" href="mailto:giuseppe.mattioli@ism.cnr.it"><giuseppe.mattioli@ism.cnr.it></a> a
écrit :
<br>
<br>
<blockquote type="cite">Dear Matthieu
<br>
I don't know which surface you want to passivate, but
remember that H can also have a strong dopant effect on
surfaces (e.g., a large upward shift of both band edges,
which has been measured on C-diamond). Therefore, I used to
passivate the unreconstructed end of III-V slabs with
*pseudo* H atoms, having fractional charge which simulate a
bulk environment surrounding the bottom layer of the slab.
They used to be in the online library but they are not
anymore (maybe for good reasons which I don't know). If you
want to try I can send you the UPF files. They are NC VBC
pseudopotentials which should not require more than
ecutwfc=40: after all you are not interested in structural
rearrangement but you only need electronic passivation of
surface states.
<br>
HTH
<br>
Giuseppe
<br>
<br>
Quoting Matthieu Fortin-Deschênes
<a class="moz-txt-link-rfc2396E" href="mailto:matthieu.fortin-deschenes@polymtl.ca"><matthieu.fortin-deschenes@polymtl.ca></a>:
<br>
<br>
<blockquote type="cite">Hi all,
<br>
<br>
I want to use hydrogen to passivate the bottom surface of
a surface slab. However, I notice that H PPs usually
require a high ecutwfc, which restricts the size of the
system I can consider.
<br>
<br>
Are there any PPs with lower required ecutwfc available
for that purpose?
<br>
And would this negatively effect the accuracy of the
calculations on the other side of the surface slab?
<br>
<br>
Thank you,
<br>
<br>
Matthieu Fortin-Deschênes
<br>
Polytechnique Montréal
<br>
<br>
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GIUSEPPE MATTIOLI
<br>
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
<br>
Via Salaria Km 29,300 - C.P. 10
<br>
I-00015 - Monterotondo Scalo (RM)
<br>
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<br>
Tel + 39 06 90672342 - Fax +39 06 90672316
<br>
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