<div dir="ltr"><div><font face="arial,helvetica,sans-serif">Dear all</font></div><div><p class="MsoNormal" style="margin:0cm 0cm 8pt"><span style="background:white;color:black;line-height:107%"><font face="arial,helvetica,sans-serif">I have studied the polarization of some metal and insulator cases using the latest version of the berryPI code. We performed the scf calculations by Wien2k14.2.<span>  </span>One of Our calculations for one of my cases using GGA method show that this case is an insulator in agreement with experimental reports. The structure of this compound is centrosymmetric in the Pm3m space group.</font></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt"><span style="background:white;color:black;line-height:107%"><font face="arial,helvetica,sans-serif">So based on the theoretical background of berryPI code it is expected that the polarization value for this compound must be zero. After running the code for this compound using this command</font></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><font face="arial,helvetica,sans-serif"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">berrypi </font><font face="arial,helvetica,sans-serif">-k6:6:6</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></font></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><font face="arial,helvetica,sans-serif"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">the </font><font face="arial,helvetica,sans-serif">results </font><font face="arial,helvetica,sans-serif">has </font><font face="arial,helvetica,sans-serif">been </font><font face="arial,helvetica,sans-serif">achieved as what was expected and copied below:</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></font></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">---------------------------</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Electronic polarization (C/m2)     sp(1)  [ 0.000000e+00,  0.000000e+00,  </font><font face="arial,helvetica,sans-serif">0.000000e+00]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Ionic polarization (C/m2)          sp(1)  [ 1.366237e-11,  1.366237e-11,  </font><font face="arial,helvetica,sans-serif">1.366237e-11]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Tot. spin polariz.=Pion+Pel (C/m2) sp(1)  [ 1.366237e-11,  1.366237e-11,  </font><font face="arial,helvetica,sans-serif">1.366237e-11]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">---------------------------</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">TOTAL POLARIZATION (C/m2)          both   [ 1.366237e-11,  1.366237e-11,  </font><font face="arial,helvetica,sans-serif">1.366237e-11]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">---------------------------</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 0pt;line-height:normal"><span style="background:white;color:black"><font face="arial,helvetica,sans-serif">We also performed calculations for another case. We have used the GGA+U (U>6eV) method for this case<span>  </span>to obtain the suitable gap compared to experiment. <span> </span>The GGA method leads to zero gap in contrast to experiment. The same as previous studied case, this structure is centrosymmetric(space group :Pm3m) </font></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 0pt;line-height:normal"><span style="background:white;color:black"><font face="arial,helvetica,sans-serif"> </font></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 0pt;line-height:normal"><span style="background:white;color:black"><font face="arial,helvetica,sans-serif"><span> </span>So we expect the zero polarization vector for this compound too,<span> b</span>ut the results show the non-zero polarization for the mentioned method in contrast to theory. Could you help me to solve this problem, please? </font></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 0pt;line-height:normal"><span style="background:white;color:black"><font face="arial,helvetica,sans-serif"> </font></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="background:white;color:black"><font face="arial,helvetica,sans-serif">In the GGA+U method and ferromagnetic polarization (with  SP calculation), after running the command:</font></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><font face="arial,helvetica,sans-serif"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">berrypi </font><font face="arial,helvetica,sans-serif">-o -k10:10:10</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></font></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">---------------------------</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Electronic polarization (C/m2)     sp(1)  [-5.253369e-</font><font face="arial,helvetica,sans-serif">01,  5.253369e-01, -5.253369e-01]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Ionic polarization (C/m2)          sp(1)  [ 3.304038e-11,  3.304038e-11,  </font><font face="arial,helvetica,sans-serif">3.304038e-11]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Tot. spin polariz.=Pion+Pel (C/m2) sp(1)  [-5.253369e-01,  5.</font><font face="arial,helvetica,sans-serif">253369e-01, -5.253369e-01]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">---------------------------</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Electronic polarization (C/m2)     sp(2)  [ 0.000000e+00,  0.000000e+00,  </font><font face="arial,helvetica,sans-serif">0.000000e+00]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Ionic polarization (C/m2)          sp(2)  [-5.</font><font face="arial,helvetica,sans-serif">253369e-01, -5.253369e-01, -5.253369e-01]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><div style="background:white;border-width:medium medium 1pt;border-style:none none solid;border-color:currentColor currentColor windowtext;padding:0cm 0cm 1pt"><font color="#000000" face="arial,helvetica,sans-serif"> </font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;padding:0cm;border:currentColor;line-height:normal"><font face="arial,helvetica,sans-serif"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Tot. spin polariz</font><font face="arial,helvetica,sans-serif">.=Pion+Pel (C/m2) sp(2)  [-5.253369e-01, -5.253369e-01, -5.253369e-01]</font></span></font></p><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;padding:0cm;border:currentColor;line-height:normal"><font face="arial,helvetica,sans-serif"><span style="color:black;font-family:"Times New Roman","serif""><font color="#222222" face="Arial">---------------------------------------------------------------------------------------<br>TOTAL POLARIZATION (C/m2)          both   [-1.050674e+00,  6.700285e-11, -1.050674e+00]<br>======================================================================================</font></span></font></p></div><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif"></font></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><font face="arial,helvetica,sans-serif"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">We </font><font face="arial,helvetica,sans-serif">also </font><font face="arial,helvetica,sans-serif">performed </font><font face="arial,helvetica,sans-serif">our </font><font face="arial,helvetica,sans-serif">calculations </font><font face="arial,helvetica,sans-serif">using </font><font face="arial,helvetica,sans-serif">the </font><font face="arial,helvetica,sans-serif">GGA </font><font face="arial,helvetica,sans-serif">method without spin polarization. after running the command</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></font></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><font face="arial,helvetica,sans-serif"><span style="color:black;font-family:"Times New Roman","serif""> <font face="arial,helvetica,sans-serif">berrypi -k10:10:10</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></font></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">---------------------------</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Electronic polarization (C/m2)     sp(1)  [-1.470943e-</font><font face="arial,helvetica,sans-serif">01, -9.456064e-02,  2.626685e-01]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Ionic polarization (C/m2)          sp(1)  [-5.</font><font face="arial,helvetica,sans-serif">253369e-01, -5.253369e-01, -5.253369e-01]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><font face="arial,helvetica,sans-serif"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">Tot. spin polariz.=Pion+Pel</font><font face="arial,helvetica,sans-serif"> (C/m2) sp(1)  [-6.724312e-01, -6.198976e-01, -2.626685e-01]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></font></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">---------------------------</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">TOTAL POLARIZATION (C/m2)          both   [-6.</font><font face="arial,helvetica,sans-serif">724312e-01, -6.198976e-01, -2.626685e-01]</font></span><span style="color:rgb(34,34,34);font-family:"Arial","sans-serif""></span></p><font color="#000000"></font><p class="MsoNormal" style="background:white;margin:0cm 0cm 10pt;line-height:normal"><span style="color:black;font-family:"Times New Roman","serif""><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">------------------------------</font><font face="arial,helvetica,sans-serif">---------------------------</font></span></p></div></div>