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<p>Hi Shu-Ting and everyone else:</p>
<p><br>
</p>
<p>I think I figured out what happened. </p>
<p><br>
</p>
<p>If we do not use spinor feature in wannier90 but include spin orbit coupling in ab initio calculations, <span>Steepest-descent minimization does not mix spin up and spin down. Thus, the orbitals keep their spin information. For vasp, it is first half up,
second half down; for quantum espresso, it is odd up, even down.</span></p>
<p><span><br>
</span></p>
<p><span>Best!</span></p>
<p><span><br>
</span></p>
<p><span>Chong</span></p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Wannier <wannier-bounces@quantum-espresso.org> on behalf of Chong Wang <ch-wang@outlook.com><br>
<b>Sent:</b> Friday, March 24, 2017 10:34:57 AM<br>
<b>To:</b> Shu-Ting Pi<br>
<b>Cc:</b> wannier@quantum-espresso.org<br>
<b>Subject:</b> Re: [Wannier] spin information of Wannier functions</font>
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<p>Hi Shu-Ting,</p>
<p><br>
</p>
<p>Here's an output example:</p>
<p><br>
</p>
<p></p>
<div> WF centre and spread 1 ( 0.000003, 1.907315, 7.573554 ) 1.90180781</div>
<div> WF centre and spread 2 ( 0.000009, 1.957394, 7.573599 ) 2.18257344</div>
<div> WF centre and spread 3 ( -0.000006, 1.874192, 7.573602 ) 2.17989134</div>
<div> WF centre and spread 4 ( 0.000016, 2.066193, 7.573556 ) 2.11466608</div>
<div> WF centre and spread 5 ( -0.000007, 1.776180, 7.573554 ) 2.12950677</div>
<div> WF centre and spread 6 ( 0.000070, -0.021664, 9.431685 ) 2.06812234</div>
<div> WF centre and spread 7 ( -0.000054, -0.014828, 9.236149 ) 2.16741854</div>
<div> WF centre and spread 8 ( -0.000000, 0.035818, 9.238267 ) 2.16653129</div>
<div> WF centre and spread 9 ( 0.000005, -0.021648, 5.715520 ) 2.06808173</div>
<div> WF centre and spread 10 ( -0.000012, -0.014840, 5.911021 ) 2.16732828</div>
<div> WF centre and spread 11 ( 0.000001, 0.035807, 5.908902 ) 2.16651165</div>
<div> WF centre and spread 12 ( 0.000017, 1.907317, 7.573556 ) 1.90176869</div>
<div> WF centre and spread 13 ( -0.000005, 1.957394, 7.573599 ) 2.18256299</div>
<div> WF centre and spread 14 ( 0.000001, 1.874187, 7.573597 ) 2.17988107</div>
<div> WF centre and spread 15 ( 0.000041, 2.066188, 7.573565 ) 2.11463312</div>
<div> WF centre and spread 16 ( -0.000049, 1.776183, 7.573547 ) 2.12949448</div>
<div> WF centre and spread 17 ( -0.000012, -0.021646, 9.431696 ) 2.06811215</div>
<div> WF centre and spread 18 ( 0.000014, -0.014842, 9.236153 ) 2.16738956</div>
<div> WF centre and spread 19 ( -0.000000, 0.035808, 9.238272 ) 2.16654910</div>
<div> WF centre and spread 20 ( 0.000064, -0.021570, 5.715492 ) 2.06802554</div>
<div> WF centre and spread 21 ( -0.000057, -0.014845, 5.911027 ) 2.16728596</div>
<div> WF centre and spread 22 ( 0.000003, 0.035764, 5.908914 ) 2.16648206</div>
<div><br>
</div>
>From WF center and spread, It seems to be first half up and second half down.
<p></p>
<p><br>
</p>
<p>Also, since you said you did a lot of test, does the spin information extracted from .spin file agree with some simple rule like <span>"odd for up, even for down"?</span></p>
<p><span><br>
</span></p>
<p><span>Best.</span></p>
<p><span><br>
</span></p>
<p><span>Chong</span></p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Shu-Ting Pi <pipidog@gmail.com><br>
<b>Sent:</b> Friday, March 24, 2017 9:25:17 AM<br>
<b>To:</b> Chong Wang<br>
<b>Cc:</b> wannier@quantum-espresso.org<br>
<b>Subject:</b> Re: [Wannier] spin information of Wannier functions</font>
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<div class="gmail_default" style="font-size:small;color:rgb(0,0,0)">Hello, </div>
<div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"><br>
</div>
<div class="gmail_default" style="font-size:small"><font color="#ff0000">"<span style="font-family:calibri,arial,helvetica,sans-serif;font-size:16px">And first half of the Wannier functions are spin up while second half are spin down."</span></font></div>
<div class="gmail_default" style="font-size:small;color:rgb(0,0,0)">I'm pretty sure it is a wrong statement ! <span style="color:rgb(34,34,34)">I did a lot test and I don't think it works.</span></div>
<div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"><span style="color:rgb(34,34,34)"><br>
</span></div>
<div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"><span style="color:rgb(34,34,34)">In some cases, spin up and down can be identified by time-reversal symmetry in SOC calculation</span><span style="color:rgb(34,34,34)">.</span></div>
<div class="gmail_default" style="font-size:small">However, even if it works, they are usually arranged as "odd for up, even for down". </div>
<div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"><span style="color:rgb(34,34,34)"> </span></div>
<div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"><span style="color:rgb(34,34,34)">Actually, in most cases, you cannot extract any information about spin without .spn file. </span></div>
<div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"><span style="color:rgb(34,34,34)"> </span></div>
<div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"><span style="color:rgb(34,34,34)">Best,</span></div>
<div class="gmail_default" style="font-size:small;color:rgb(0,0,0)"><span style="color:rgb(34,34,34)">Shu-Ting</span></div>
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<div class="gmail_extra"><br>
<div class="gmail_quote">On Thu, Mar 23, 2017 at 6:04 PM, Chong Wang <span dir="ltr">
<<a href="mailto:ch-wang@outlook.com" target="_blank">ch-wang@outlook.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div id="m_1169400058190977155divtagdefaultwrapper" dir="ltr" style="font-size:12pt;color:#000000;font-family:Calibri,Arial,Helvetica,sans-serif">
<p>Hi,</p>
<p><br>
</p>
<p>I am told that in the presence of spin-orbit coupling, the Wannier functions generated by Wannier90 package are eigenstates of s_z (spin operator in the z direction), even without a .spn input file. And first half of the Wannier functions are spin up while
second half are spin down.</p>
<p><br>
</p>
<p>As far as I am concerned, Wannier90 package does not know anything about spin if .spn files are not present. Then why Wannier functions should end up to be eigenstates of s_z?</p>
<p><br>
</p>
<p>Chong Wang</p>
<p>Institute of Advanced Study, Tsinghua University</p>
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