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<p><font size="2"><span style="font-size:10pt">Dear All,<br>
<br>
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<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US">I want to study two polymorphs of an iron containing compound. Each polymorph has 4 symmetrically equivalent Fe-sites (space group Pnma). One of the polymorphs have the Fe-sites at the
inversion centers of the crystal and the other does not. Looking at the band structure I find 20 isolated low-energy bands of strong d-orbital character, with no hybridization with other states, and a small bandwidth. So I want to extract 20 wannier functions
to construct a low energy model. In order for the model Hamiltonian to be symmetrical I would like to have the wannier functions well centered exactly at Fe atomic positions, and those WFs should be interchangeable between them by crystal symmetry operations.
</span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US"> </span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US">When using QE with pw2wannier90 and wannier90, I am able to extract non-symmetry adapted WFs that represent the band structure perfectly, but the wannier centres are slightly misplaced
from the Fe sites, and therefore I have 20 non inequivalent WF and slightly different Hamiltonian matrix elements between sites. However when I try to do the calculation with the ‘site_symmetry’ tag set to .true., I find that the wannier functios keep being
misplaced and look exactly the same as the ones without symmetry.</span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US"> </span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US">Looking further into the .sym and .dmn I find that the only operation appearing is</span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US"> </span><font size="2"><span style="font-size:10pt"></span></font></p>
</span></font><font size="2"><span style="font-size:10pt">
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US"> 1.0000 0.0000 0.0000</span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US"> 0.0000 1.0000 0.0000</span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US"> 0.0000 0.0000 1.0000</span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US"><br>
</span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US"> 0.0000 0.0000 0.0000<br>
</span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US"> </span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US">And the header of the .dmn file is</span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US"> </span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US">170 1 40 40</span></p>
<p class="MsoNormal"><span style="mso-ansi-language:EN-US" lang="EN-US"> </span></p>
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-ansi-language:
EN-US;mso-fareast-language:ES;mso-bidi-language:AR-SA" lang="EN-US">So, definitely the calculation has not
detected the symmetry of the structure, because only one operation is applied and the amount of irreducible k-points (which is 18 in my scf calculation) is 40. I’m sure I am missing something</span></span></font><font size="2"><span style="font-size:10pt"></span></font><font size="2"><span style="font-size:10pt">,
I think that the fact that I had to use explicit 40 k-points for the 'nscf' calculation to match the k-point list in the .win file Is contrary to the calculation considering any symmetry. So thats why the later pw2wannier90 run just does not consider any symmetry.</span></font><br>
<font size="2"><span style="font-size:10pt"></span></font>
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<font size="2"><span style="font-size:10pt"><br>
</span></font>
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<p><font size="2"><span style="font-size:10pt">Any suggestions for solving this would be much appreciated.<br>
</span></font></p>
<p><font size="2"><span style="font-size:10pt"><br>
</span></font></p>
<p><font size="2"><span style="font-size:10pt">Best regards,<br>
Oier.</span></font><br>
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