<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12pt"><div id="yiv6973699019"><div class="yiv6973699019yqt3147139502" id="yiv6973699019yqtfd81230"><div><div style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12pt;">Dear Oleg Rubel,<div class="yiv6973699019yahoo_quoted" id="yiv6973699019yui_3_13_0_7_1383319853621_14" style="display:block;"><div class="yiv6973699019yui_3_13_0_1_1383319853621_9272" id="yiv6973699019yui_3_13_0_1_1383319853621_9373" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12pt;"><div class="yiv6973699019yui_3_13_0_1_1383319853621_9273" id="yiv6973699019yui_3_13_0_1_1383319853621_9372" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande,
sans-serif;font-size:12pt;"><span id="yiv6973699019yui_3_13_0_1_1383319853621_9386"></span><div class="yiv6973699019y_msg_container" id="yiv6973699019yui_3_13_0_1_1383319853621_9377"><div id="yiv6973699019"><div id="yiv6973699019yui_3_13_0_1_1383319853621_9376"><div class="yiv6973699019yui_3_13_0_1_1383319853621_9275" id="yiv6973699019yui_3_13_0_1_1383319853621_9375" style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12pt;"><div class="yiv6973699019yui_3_13_0_1_1383319853621_9276" id="yiv6973699019yui_3_13_0_1_1383319853621_9378" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;background-color:transparent;font-style:normal;"><br clear="none"><span></span></div><div class="yiv6973699019yui_3_13_0_1_1383319853621_9277" id="yiv6973699019yui_3_13_0_1_1383319853621_9380" style="color:rgb(0, 0,
0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;background-color:transparent;font-style:normal;"><span id="yiv6973699019yui_3_13_0_1_1383319853621_9379">I have calculated the spontaneous polarization for BiCoO3 in tetragonal structure, and then, <br clear="none"></span></div><div class="yiv6973699019yui_3_13_0_1_1383319853621_9278" id="yiv6973699019yui_3_13_0_1_1383319853621_9382" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;background-color:transparent;font-style:normal;"><span id="yiv6973699019yui_3_13_0_1_1383319853621_9381">I have got different results between [0 - 2] range and [-1 -
+1] range.</span></div><div class="yiv6973699019yui_3_13_0_1_1383319853621_9279" id="yiv6973699019yui_3_13_0_1_1383319853621_9383" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;background-color:transparent;font-style:normal;"><span><br clear="none"></span></div><div class="yiv6973699019yui_3_13_0_1_1383319853621_9280" id="yiv6973699019yui_3_13_0_1_1383319853621_9385" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;background-color:transparent;font-style:normal;"><span id="yiv6973699019yui_3_13_0_1_1383319853621_9384">Please I have some questions:</span></div><div class="yiv6973699019yui_3_13_0_1_1383319853621_9281" id="yiv6973699019yui_3_13_0_1_1383319853621_9399" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande,
sans-serif;background-color:transparent;font-style:normal;"><span><br clear="none"></span></div><div class="yiv6973699019yui_3_13_0_1_1383319853621_9282" id="yiv6973699019yui_3_13_0_1_1383319853621_9398" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;background-color:transparent;font-style:normal;"><span id="yiv6973699019yui_3_13_0_1_1383319853621_9397">- What is the significance of negative values of total polarization ?</span></div><div class="yiv6973699019yui_3_13_0_1_1383319853621_9283" id="yiv6973699019yui_3_13_0_1_1383319853621_9396" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;background-color:transparent;font-style:normal;"><span id="yiv6973699019yui_3_13_0_1_1383319853621_9395">- Why the values of P_x and P_y is not ~0 ?</span></div><div
class="yiv6973699019yui_3_13_0_1_1383319853621_9284" id="yiv6973699019yui_3_13_0_1_1383319853621_9393" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;background-color:transparent;font-style:normal;"><span id="yiv6973699019yui_3_13_0_1_1383319853621_9402">- Is my calculation is true ?</span></div><div class="yiv6973699019yui_3_13_0_1_1383319853621_9285" id="yiv6973699019yui_3_13_0_1_1383319853621_9420" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;background-color:transparent;font-style:normal;"><span><br clear="none"></span></div><div class="yiv6973699019yui_3_13_0_1_1383319853621_9286" id="yiv6973699019yui_3_13_0_1_1383319853621_9404" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande,
sans-serif;background-color:transparent;font-style:normal;"><span id="yiv6973699019yui_3_13_0_1_1383319853621_9403">Please find in attached files the BiCoO3.struct, BiCoO3.berrypi (for non-centrosymmery case)
and </span><br class="yiv6973699019" clear="none"><span id="yiv6973699019yui_3_13_0_1_1383319853621_9419">BiCoO3.berrypi (for centrosymmery case).</span></div><div class="yiv6973699019yui_3_13_0_1_1383319853621_9287" id="yiv6973699019yui_3_13_0_1_1383319853621_9405" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;background-color:transparent;font-style:normal;"><br clear="none"><span></span></div><div class="yiv6973699019yui_3_13_0_1_1383319853621_9288" id="yiv6973699019yui_3_13_0_1_1383319853621_9418" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;background-color:transparent;font-style:normal;"><span>NB: the </span><span id="yiv6973699019yui_3_13_0_1_1383319853621_9417">spontaneous polarization of BiCoO3 in literature is: 179 uCm/<br clear="none"></span></div><div
id="yiv6973699019yui_3_13_0_1_1383319853621_9406"><br clear="none">Thanks in advance. <br clear="none"><br clear="none"></div><div id="yiv6973699019yui_3_13_0_1_1383319853621_9407">-------------------------------------------------------<br clear="none">Mostefa DJERMOUNI<br clear="none">Modeling and Simulation in Materials Science Laboratory<br clear="none">University of Sidi Bel-Abbes<br clear="none">22000 Sidi Bel-Abbes, Algeria<br clear="none">Tel: +213 795 626 105<br clear="none">-------------------------------------------------------</div></div></div></div><br clear="none"><br clear="none"></div> </div> </div> </div> </div></div></div></div></div></body></html>