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<p>Dear Nathan,</p>
<p><br>
</p>
<p>The results for kx=0.5 near 0.8 on the x-axis look a bit
suspicious. I can't really identify the problem from the Wannier
input file alone though.</p>
<p>In the meantime however, I have updated the Bi example with a
pseudopotential that works with newer QE versions: <a
moz-do-not-send="true"
href="https://github.com/Z2PackDev/Z2Pack/tree/dev/current/examples/fp/espresso/6.2/Bi">https://github.com/Z2PackDev/Z2Pack/tree/dev/current/examples/fp/espresso/6.2/Bi</a></p>
<p><br>
</p>
<p>Maybe you can find the difference by studying the example, I have
attached the plot produced by the example for reference.</p>
<p><br>
</p>
<p>Best,</p>
<p>Dominik<br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 28.01.21 13:27, Johnson, Nathan
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:a9ba605d0a054a65bae632d109075058@student.liverpool.ac.uk">
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<span
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color:black;mso-fareast-language:EN-GB">Hi Dominik,<o:p></o:p></span></p>
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style="margin-bottom:12.0pt;line-height:normal;background:
white">
<span
style="font-size:12.0pt;mso-ascii-font-family:Calibri;mso-fareast-font-family:"Times
New
Roman";mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;
color:black;mso-fareast-language:EN-GB"><br>
Thanks for your reply and insight. </span></p>
<p class="MsoNormal"
style="margin-bottom:12.0pt;line-height:normal;background:
white">
<span
style="font-size:12.0pt;mso-ascii-font-family:Calibri;mso-fareast-font-family:"Times
New
Roman";mso-hansi-font-family:Calibri;mso-bidi-font-family:Calibri;
color:black;mso-fareast-language:EN-GB">I have attached
some new plots for the systems with .win files being the
attached bi.win. The Chern and Z2 invariants of each plot
are 0. Are these outputs correct?</span></p>
<p class="MsoNormal"
style="margin-bottom:12.0pt;line-height:normal;background:
white">
<span style="font-size: 12pt;">Best wishes,<br>
</span><span style="font-size: 12pt;">Nathan</span></p>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>From:</b>
Dominik Gresch <a class="moz-txt-link-rfc2396E" href="mailto:greschd@gmx.ch"><greschd@gmx.ch></a><br>
<b>Sent:</b> 12 January 2021 22:25:00<br>
<b>To:</b> Johnson, Nathan; <a class="moz-txt-link-abbreviated" href="mailto:z2pack@lists.phys.ethz.ch">z2pack@lists.phys.ethz.ch</a><br>
<b>Subject:</b> Re: Output for Bi Example</font>
<div> </div>
</div>
<div>
<p>Dear Nathan,</p>
<p><br>
</p>
<p>I am unsure why the pseudopotential included in the example
no longer works; maybe there was a change in the format that
is acceptable by QE. Since this error has been reported
before, I have
<a href="https://github.com/Z2PackDev/Z2Pack/issues/108"
moz-do-not-send="true">created an issue</a> to investigate
it.<br>
<br>
In any case, at least for the "<span
style="font-size:12.0pt; font-family:"Times New
Roman",serif"><a
href="https://www.quantum-espresso.org/upf_files/Bi.pbe-dn-kjpaw_psl.1.0.0.UPF"
target="_blank" moz-do-not-send="true"><span
style="color:windowtext; text-decoration:none">Bi.pbe-dn-kjpaw_psl.1.0.0.UPF</span></a></span>"
pseudopotential the input files need changing because the
"z_valence" of the pseudo is 15 (instead of 5 for the
previous pseudopotential). That means that we will have 30
instead of 10 occupied states.</p>
<p><br>
</p>
<p>That means `nbnd` in `bi.nscf.in` needs to be changed to
some number larger than 30, let's pick 36 for example
(adding a few to make sure all occupied states are
converged). In the .win file, we will need to change
`num_wann` and `num_bands` to 30, and `exclude_bands` to `31
- 36`.</p>
<p>These values generally need to be changed when
investigating different systems, such that the occupied
subspace is considered.</p>
<p><br>
</p>
<p>From the plots, you can also see that the results are
incorrect: The WCC should follow a smooth evolution. Abrupt
changes in WCC position are generally a sign of trouble.
They can happen (mostly when the direct band gap is very
low) but it should eventually converge to a continuous
evolution as more "lines" are added in the convergence
routine. The evaluation of the topological invariants relies
on this continuous evolution, meaning that the results are
meaningless if the WCC evolution is discontinuous.</p>
<p><br>
</p>
<p>Hope this helps,<br>
</p>
<p><br>
</p>
<p>Best regards,</p>
<p>Dominik<br>
</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 11.01.21 14:36, Johnson,
Nathan wrote:<br>
</div>
<blockquote type="cite">
<div id="divtagdefaultwrapper" dir="ltr" style="">
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">Dear
recipient,</span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">I have
Z2Pack 2.1.1 set up with first principles code as
Quantum Espresso version 6.4.1 with interface to
Wannier90 3.1.0. I have run calculations for Z2Pack's
Bi example and would like to see how our output
compares.</span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">Calculations
have been performed for two Bi systems with
pseudopotentials <a
href="https://www.quantum-espresso.org/upf_files/Bi.pbe-dn-kjpaw_psl.1.0.0.UPF"
target="_blank" moz-do-not-send="true"><span
style="color:windowtext; text-decoration:none">Bi.pbe-dn-kjpaw_psl.1.0.0.UPF</span></a> and <u>Bi.pbe-d-mt.UPF</u>
using the provided run.py script. These
pseudopotentials were used instead of the supplied
pseudopotential as the error,</span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">"</span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">
Error in routine readpp (1):</span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">
file ../input/Bi_MT_PBE.UPF not readable</span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">", was
returned during an attempted SCF run using the
pseudopotential. The values used for converge
parameters were the same values as those corresponding
to converge parameters in the _run.py file located in
the 'surface' folder of the Z2Pack 2.1.1
distribution. </span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">What
ought the output for this example be?</span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">I have
found a Z2Pack WCC plot corresponding to 'half the k<sub>z</sub>=0
plane of Bismuth' on page 82 of the Topological Matter
School Lectures, however, the surfaces of the example
seem to be half the k<sub>x</sub>=0 and k<sub>x</sub>=0.5
planes. With the working assumption that the
allotrope of Bi corresponding to the Topological
Matter School plot is the same allotrope of Bi as that
for which the ionic configuration of the example
corresponds to, I also performed calculations for both
Bi systems using ‘surface=lambda s, t: [t, s / 2, 0]’.
I am uncertain, however, that the vertical axis of the
WCC plots generated by calculations on this surface
would correspond to the x-axis of direct space.</span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">I
attach the output of aforementioned calculations -
please find attached the .win file for both Bi systems
and WCC plots.
</span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">Looking
forward to hearing from you,</span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif"> </span></p>
<p class="MsoNormal" style="margin-bottom:0cm;
line-height:normal"><span style="font-size:12.0pt;
font-family:"Times New Roman",serif">Best
wishes,</span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;
line-height:107%; color:black; background:white">Nathan
Johnson, PhD student UK</span></p>
<br>
<div>
<div><br>
</div>
</div>
</div>
</blockquote>
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