<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, Sans-Serif;font-size:12pt"><div style="margin-bottom:0in;" align="LEFT"><br clear="none"></div><div style="margin-bottom:0in;" align="LEFT">Dear Prof. Rubel and Prof. Sheikh,</div><div class="">
<font class="" face="Calibri"><span class="" style="border-collapse:collapse;font-size:11px;"><br clear="none"></span></font></div><div><span class="" style="border-collapse:collapse;font-family:arial, sans-serif;font-size:13px;">> 1) Take the structure files enclosed (I assume they are not different from yours).</span></div>
<div class=""><span class="" style="border-collapse:collapse;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:16px;">I used your stature file and found that it is identical to my structure.</span></div>
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</font></span></div><div class=""><div class=""><span class="" style="border-collapse:collapse;font-family:Calibri;font-size:11px;">>Please, make sure that you have the latest version of WIEN2WANNIER (see the post <a rel="nofollow" shape="rect" target="_blank" href="https://mail.google.com/mail/%22" style="color:rgb(17,85,204);"><span style="text-decoration:underline;color:rgb(5,61,245);">http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg09119.html</span></a>).</span></div>
<div><span class="" style="border-collapse:collapse;font-family:Calibri;font-size:11px;"><br clear="none"></span></div></div><div class=""><span class="" style="border-collapse:collapse;font-family:arial, sans-serif;font-size:13px;"></span><div class="">
<span class="" style="border-collapse:collapse;font-family:arial, sans-serif;font-size:13px;"></span><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;font:normal normal normal 10px/normal Arial;">
> My computed effective charge seems to almost the same as computed by Dr. Rubel. </div></div><span class="" style="border-collapse:collapse;font-family:Arial;font-size:10px;">I think you are using older versions of either BerryPI or Wien2Wannier or both. Please use the latest version of BerryPI (v1.0) <a rel="nofollow" shape="rect" target="_blank" href="https://github.com/spichardo/BerryPI%22%20%5Ct%20%22_blank" style="color:rgb(17,85,204);"><span style="font:normal normal normal 12px/normal 'Times New Roman';text-decoration:underline;color:rgb(5,61,245);">https://github.com/spichardo/BerryPI</span></a><span style="font:normal normal normal 12px/normal 'Times New Roman';"> and Wien2Wannier (v0.97) <a rel="nofollow" shape="rect" target="_blank" href="http://www.wien2k.at/reg_user/unsupported/wien2wannier/%22%20%5Ct%20%22_blank" style="color:rgb(17,85,204);"><span
style="text-decoration:underline;color:rgb(5,61,245);">http://www.wien2k.at/reg_user/unsupported/wien2wannier/</span></a>.</span></span><span class="" style="border-collapse:collapse;font-family:arial, sans-serif;font-size:13px;"></span><span class="" style="border-collapse:collapse;font-family:'Times New Roman';font-size:12px;">The
older version of BerryPI (v0.1) had some problem in wrapping of phases
which has been fixed in version 1.0. Also, the older versions of
Wien2wannier was having an issue in identifying the complex calculation <span style="font:normal normal normal 10px/normal Arial;">(see the post <a rel="nofollow" shape="rect" target="_blank" href="http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg09119.html%22%20%5Ct%20%22_blank" style="color:rgb(17,85,204);"><span style="text-decoration:underline;color:rgb(5,61,245);">http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg09119.html</span></a>)</span></span><span class="" style="border-collapse:collapse;font-family:arial, sans-serif;font-size:13px;"></span><div class="">
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</font></span></div><div class=""><span class="" style="border-collapse:collapse;"><font class="" face="HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif" size="3">I
installed the latest version of BerriPI, WIEN2WANNIER, WANNIER90,
NUMPHY, and could reproduce the results of Prof. Rubel in agreement with
reported values in literature. But, we still do not know what was the
source of problem of the </font></span><span class="" style="border-collapse:collapse;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:medium;">BerryPI or WIEN2WANNIER </span><span class="" style="border-collapse:collapse;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:medium;">old version which resulted in an unsatisfactory result. We are interested in realizing the bug(s) of the old version(s).</span></div>
<div class=""><span class="" style="border-collapse:collapse;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:medium;"> </span></div>
<div class=""><span class="" style="border-collapse:collapse;font-family:arial, sans-serif;font-size:13px;">>
2) create directories 'lambda1' and 'lambda2'. In both cases I displace
the Ga atom by +0.01 and -0.01 along z-axis. There is nothing specific
about the choice of displacements. In fact 0.005 should work too. I
encourage you to test the convergence and plot Z as a function of
displacement. I do not recommend to go for displacements larger than
0.01</span><span class="" style="border-collapse:collapse;"><font class="" face="HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif" size="3"><br clear="none">
</font></span><span class="" style="border-collapse:collapse;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;"></span><div class="" style="font-size:large;">
<span class="" style="border-collapse:collapse;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:16px;"><br clear="none"></span></div><div class="">
<font class="" size="3">I did it, and the results which nicely confirm your prediction, do not depend on the Z.</font></div><div class=""><font class="" size="3"><br clear="none"></font></div>
<div class=""><font class="" size="3">Now I am working on your following comments:</font></div><div class=""><font class="" size="3"><br clear="none"></font></div><div class="">
<div style="margin:0.0px 0.0px 0.0px 0.0px;font:12.0px 'Times New Roman';">> In order to address the spontaneous polarization, we need two cases:<br clear="none">
(a) the initial reference structure and<br clear="none">
(b) your relaxed structure.<br clear="none">
The spontaneous polarization is the difference between them. Please,
look in the literature what is used as a reference structure. The choice
of structure (a) for GaN is not obvious to me. Once you determine that,
I can help you to move on.<br clear="none">
</div><div style="margin:0.0px 0.0px 0.0px 0.0px;font:12.0px 'Times New Roman';"><br clear="none"></div></div><span class="" style="border-collapse:collapse;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:medium;">Would you give me some clue to reach the goal sooner? </span><span class="" style="border-collapse:collapse;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;"></span><div class="">
<font class="" size="3"><br clear="none"></font></div><div class=""><font class="" size="3">PS:
We detected that init.sh ha a bug. If the version of the installed
numpy is 1.6.2, the init.sh works fine. But, if the version is different
depending on the linux version, e.g., numpy 1.4.1, then init.sh script
tries to install numpy 1.6.2 on .local directory. This is not necessary,
as already bumpy 1.4.1 is installed. Although the installation on
.local directory is successful by init.sh, but init.sh cannot uses it,
because it is not installed in the default path. So, for such a case, we
changed 1.6.2 to 1.4.1 in init.sh to prevent its stop in changing the
.bashrc automatically. We just thought that you maybe in next version
would like to fix this small bug.</font></div>
<div class=""><font class="" size="3"> </font></div><span class="" style="border-collapse:collapse;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:medium;">Thank you for your attentions,</span><span class="" style="border-collapse:collapse;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-size:16px;"></span><div dir="ltr" style="margin-bottom:0in;" align="LEFT">
SH.Rahimi</div></div></div></body></html>