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<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 moz-do-not-send="true"
href="https://github.com/Z2PackDev/Z2Pack/issues/108">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"><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"
cite="mid:e7377ed912504ce789ed17e38f672cc0@student.liverpool.ac.uk">
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<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>
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<div><br>
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