<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
</head>
<body>
<div name="messageBodySection" style="font-size: 14px; font-family: -apple-system, BlinkMacSystemFont, sans-serif;">Hello Everyone,
<div><br /></div>
<div>I am attempting to perform a Wannierization of the valence bands of PbTe. I have performed a spin orbit calculation in QE (with lspinorb = true and noncolin = true). I did this using a 16x16x16 shifted grid for the scf calculation and an 8x8x8 full grid for the nscf calculation. Based on the results of a non-SO calculation, I know that the bands are primarily of Te-p and Pb-s character.</div>
<div><br /></div>
<div>In the Wannierization step, I use the following input:</div>
<div><br /></div>
<div>
<div>num_bands = 10</div>
<div>num_wann = 10</div>
<div>num_iter = 1000</div>
<div>conv_window = 10</div>
<div>conv_tol = 1e-5</div>
<div>spinors = true</div>
<div><br /></div>
<div>bands_plot = true</div>
<div>begin kpoint_path </div>
<div>L 0.500 0.500 0.500 G 0.000 0.000 0.000 </div>
<div>G 0.000 0.000 0.000 X 0.000 0.500 0.500</div>
<div>X 0.000 0.500 0.500 W 0.250 0.750 0.500</div>
<div>W 0.250 0.750 0.500 L 0.500 0.500 0.500</div>
<div>L 0.500 0.500 0.500 G 0.000 0.000 0.000</div>
<div>G 0.000 0.000 0.000 K 0.375 0.750 0.375 </div>
<div>end kpoint_path </div>
<div><br /></div>
<div>begin projections</div>
<div>c=-3.046778,3.731389,3.046598:pz</div>
<div>c=-2.754606,2.754517,2.755727:s</div>
<div>c=-3.731378,3.046842,3.046648:pz</div>
<div>c=-3.047456,3.047471,3.731244:pz</div>
<div>c=-3.145233,3.145233,6.290419:s</div>
<div>end projections</div>
<div><br /></div>
<div>mp_grid = 8 8 8</div>
<div><br /></div>
<div>begin kpoints</div>
<div> **list of 512 points identical to nscf calculation**<br /></div>
<div>end kpoints</div>
<div><br /></div>
<div>begin atoms_frac</div>
<div> Pb 0.000 0.000 0.000</div>
<div> Te 0.500 0.500 0.500</div>
<div>end atoms_frac</div>
<div><br /></div>
<div>begin unit_cell_cart</div>
<div>Ang</div>
<div>-3.145186 0.000000 3.145186</div>
<div> 0.000000 3.145186 3.145186</div>
<div>-3.145186 3.145186 0.000000</div>
<div>end unit_cell_cart</div>
</div>
<div><br /></div>
<div>Unfortunately, even after 1000+ iterations, though my spreads are in the range of 4-5 Ang^2, they aren't converged, and I can only get to a DLTA of approximately 1E-5. If I look at the band structure, I see a difference between the Kramer’s degenerate states and wiggles at the high symmetry points. Moreover, unless I explicitly set the conv_tol to 1e-5 and convert_window to 10, it will basically iterate to the end and give me results that are even worse. It seems like gradient descent can’t find the global minima. Here’s a grep of the output and final state:</div>
<div><br /></div>
<div>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures">+--------------------------------------------------------------------+<-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> | Iter Delta Spread RMS Gradient Spread (Ang^2) Time |<-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> +--------------------------------------------------------------------+<-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 0 0.886E+02 0.0000000000 88.5961756930 2.02 <-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 1 -0.193E+02 3.6519324709 69.2719457144 2.09 <-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 2 -0.119E+02 2.9217065446 57.4196136819 2.16 <-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 3 -0.789E+01 2.2523091155 49.5285805341 2.23 <-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 4 -0.405E+01 1.8769695123 45.4786941630 2.29 <-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 5 -0.117E+01 1.4810561663 44.3102929602 2.36 <-- CONV</span></p>
</div>
<div>
<div style="font-variant-ligatures: no-common-ligatures">
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> ...<br /></span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 732 -0.954E-05 0.0812066914 41.5149635930 50.03 <-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 733 -0.485E-05 0.2124621933 41.5149587471 50.09 <-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 734 -0.587E-05 0.0551927135 41.5149528784 50.16 <-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 735 -0.479E-05 0.2156962496 41.5149480855 50.22 <-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 736 -0.461E-05 0.0560167032 41.5149434756 50.28 <-- CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"> 737 -0.365E-05 0.1892001198 41.5149398256 50.35 <— CONV</span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"><br /></span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);">Final State</p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"> WF centre and spread 1 ( -2.924839, 3.504327, 3.469653 ) 4.69435114</p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"> WF centre and spread 2 ( -2.925054, 3.503452, 3.470009 ) 4.71351191</p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"> WF centre and spread 3 ( -2.673238, 2.673025, 2.971221 ) 3.59977954</p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"> WF centre and spread 4 ( -2.672922, 2.673446, 2.971132 ) 3.60028628</p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"> WF centre and spread 5 ( -3.503953, 2.924918, 3.470236 ) 4.70571734</p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"> WF centre and spread 6 ( -3.505087, 2.924613, 3.471128 ) 4.70069921</p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"> WF centre and spread 7 ( -3.482302, 3.482023, 2.682537 ) 3.93809935</p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"> WF centre and spread 8 ( -3.481404, 3.482794, 2.682584 ) 3.93941997</p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"> WF centre and spread 9 ( -3.145268, 3.145207, 6.293045 ) 3.82072386</p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"> WF centre and spread 10 ( -3.145260, 3.145161, 6.293306 ) 3.80235121</p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"><span style="font-variant-ligatures: no-common-ligatures"></span></p>
<p style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; background-color: rgb(255, 255, 255);"> Sum of centres and spreads (-31.459326, 31.458966, 37.774852 ) 41.51493983</p>
</div>
</div>
<div><br /></div>
<div>I should point out that when doing the non spin-orbit case, I didn't have a problem achieving convergence with spreads in the 2-3 Ang^2 range and DLTAs of 1E-11.</div>
<div><br /></div>
<div>I tried various initial guesses for the projections, going so far as to using the centers from the non-SO MLWFs, but no luck. I would greatly appreciate any guidance. Thank you in advance.</div>
<div><br /></div>
<div>Sincerely,</div>
</div>
<div name="messageSignatureSection" style="font-size: 14px; font-family: -apple-system, BlinkMacSystemFont, sans-serif;"><br />
Prashant Padmanabhan
<div>---</div>
<div>Post-doctoral Researcher</div>
<div>II. Physics Institute</div>
<div>University of Cologne</div>
<div>50823 Cologne</div>
<div>Germany</div>
<div><br /></div>
</div>
<div name="messageReplySection" style="font-size: 14px; font-family: -apple-system, BlinkMacSystemFont, sans-serif;"><br />
<div></div>
</div>
</body>
</html>