<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Dear all,</div><div class=""><br class=""></div><div class="">I have great interest in the calculation of orbital magnetization (OM) implemented in Wannier formalism [Lopez et al., PRB 85, 014435 (2012)]. Indeed, I can repeat all results of bcc Fe in this paper, by following the example19 in the tutorial. In example19, the integration is adopted in full Brillouin zone (BZ). Thus, the computational cost is not too much because only 18 Wannier functions in Fe and the convergence of OM with respect to k-mesh can be easily reached. However, the irreducible BZ integration must be adopted if a system contains more than hundreds of orbitals or the convergence is difficult .</div><div class=""><br class=""></div><div class="">For this purpose<font color="#3d3d3d" face="Arial, sans-serif" class="">, I fist test the irreducible BZ integrations of OM in bcc Fe, by setting the tag "wanint_kpoint_file = true” in the win file and providing the </font><span style="color: rgb(61, 61, 61); font-family: Arial, sans-serif;" class="">irreducible </span><font color="#3d3d3d" face="Arial, sans-serif" class="">k-points and their weights in file “kpoint.dat”. I have read the code in berry.F90 and other related subroutines, and I guess that the k-points are given in relative coordinates of the reciprocal lattice and the sum of weights equals to one. The </font><span style="color: rgb(61, 61, 61); font-family: Arial, sans-serif;" class="">irreducible </span><font color="#3d3d3d" face="Arial, sans-serif" class="">k-points are generated by using the “pw.x”. The calculated OMs are very different between the full and </font><span style="color: rgb(61, 61, 61); font-family: Arial, sans-serif;" class="">irreducible BZ integrations.</span></div><div class=""><br class=""></div><div class=""><div class="">For example, if I use full BZ <span style="color: rgb(61, 61, 61); font-family: Arial, sans-serif;" class="">integration with the k-mesh of </span>50x50x50, the result<span style="color: rgb(61, 61, 61); font-family: Arial, sans-serif;" class=""> is:</span></div></div><div class=""><font color="#3d3d3d" face="Arial, sans-serif" class=""><br class=""></font></div><div class=""><font color="#3d3d3d" face="Arial, sans-serif" class=""><div class=""> M_orb (bohr magn/cell) x y z</div><div class=""> ======================</div><div class=""> Local circulation : -0.0000 -0.0000 0.0935</div><div class=""> Itinerant circulation: 0.0000 -0.0000 -0.0187</div><div class=""> --------------------------------------------------------</div><div class=""> Total : 0.0000 -0.0000 0.0749</div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">This value is identical to the paper PRB 2012. On the other hand, if use the irreducible BZ integration with 102 k-points (the file “kpoint.dat" is attached), the result is</div></font><font color="#3d3d3d" face="Arial, sans-serif" class=""><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><div class=""> M_orb (bohr magn/cell) x y z</div><div class=""> ======================</div><div class=""> Local circulation : -0.0153 0.0040 0.0932</div><div class=""> Itinerant circulation: 0.0030 0.0027 -0.0163</div><div class=""> --------------------------------------------------------</div><div class=""> Total : -0.0123 0.0066 0.0768</div></div></font></div><div class=""><br class=""></div><div class="">Could anyone tell me what mistakes I have did? Please ask for other details I may forget to show. Any suggestions will be appreciated.</div><div class=""><br class=""></div><div class="">By the way, I noted that someone has asked that the DOS calculations with full and irreducible BZs are also different. He generated file “kpoint.dat” by both abinit and elk. </div><div class=""><a href="http://mailman.qe-forge.org/pipermail/wannier/2014-December/000929.html" class="">http://mailman.qe-forge.org/pipermail/wannier/2014-December/000929.html</a></div><br class=""><div apple-content-edited="true" class="">
<div class=""><div class="">Wanxiang Feng</div><div class=""><div class="">————————————————</div><div class="">School of Physics</div><div class="">Beijing Institute of Technology</div><div class="">Beijing 100081, China</div></div></div><div class=""><br class=""></div></div></body></html>