<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 05 Jul 2015, at 18:29, Gul Rahman <<a href="mailto:gulrahman@qau.edu.pk" class="">gulrahman@qau.edu.pk</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class=""><div class=""><div class=""><div class=""><div class=""><div class=""><div class=""><div class=""><div class="">Dear All,<br class=""></div>I am doing some test calculations on 2D Sn and comparing QE with SIESTA. Both QE and SIESTA almost give the same results (DOS, lattice constnat, charge,,). However, I have problem with the band structure. I want to plot the band structure in <br class=""></div>0.0,0.0 0.0 to 0.33,0.330.00 to 0.5,0.0,0.0.<br class=""></div>I either write a python code or jut do by hand to put the number of points in the input file for the band structure calculation.<br class="">_POINTS crystal<br class="">29<br class="">0.00000 0.00000 0.00000 1.0000<br class="">0.03000 0.03000 0.00000 1.0000<br class="">0.06000 0.06000 0.00000 1.0000<br class="">0.09000 0.09000 0.00000 1.0000<br class="">0.12000 0.12000 0.00000 1.0000<br class="">0.15000 0.15000 0.00000 1.0000<br class="">0.18000 0.18000 0.00000 1.0000<br class="">0.21000 0.21000 0.00000 1.0000<br class="">0.24000 0.24000 0.00000 1.0000<br class="">0.27000 0.27000 0.00000 1.0000<br class="">0.30000 0.30000 0.00000 1.0000<br class="">0.33000 0.33000 0.00000 1.0000<br class="">0.34000 0.31060 0.00000 1.0000<br class="">0.35000 0.29120 0.00000 1.0000<br class="">0.36000 0.27180 0.00000 1.0000<br class="">0.37000 0.25240 0.00000 1.0000<br class="">0.38000 0.23300 0.00000 1.0000<br class="">0.39000 0.21360 0.00000 1.0000<br class="">0.40000 0.19420 0.00000 1.0000<br class="">0.41000 0.17480 0.00000 1.0000<br class="">0.42000 0.15540 0.00000 1.0000<br class="">0.43000 0.13600 0.00000 1.0000<br class="">0.44000 0.11660 0.00000 1.0000<br class="">0.45000 0.09720 0.00000 1.0000<br class="">0.46000 0.07780 0.00000 1.0000<br class="">0.47000 0.05840 0.00000 1.0000<br class="">0.48000 0.03900 0.00000 1.0000<br class="">0.49000 0.01960 0.00000 1.0000<br class="">0.50000 0.00020 0.00000 1.0000<br class=""></div><br class=""></div>when I used it, I always see crossing points in the band structure. Pls, see the attached file and you can see crossing points not only around Dirac point, but also above that.<br class=""></div>Could you plz let me know why I am facing this problem whenever I try the band structure of any material and I will have these crossing lines.<br class=""></div></div></div></div></div></blockquote><div><br class=""></div><div>Are you referring to the crossings around -1.5 and + 1.5 eV? These are just spurious, and are due to the fact that because consecutive points are connected in the plot, if the ordering of the bands is not the proper one, a point in a lower bands is connected not to the next point in the same band but to a point in a higher band. Plotting the band structure only with points or calculating the band structure with a larger number of k-points solves the problem,</div><div><br class=""></div><div>Other crossings (e.g. around 4 eV) are instead the results of the calculation, so if you do not expect them it means that your input files do contain some error (e.g. k-points coordinates).</div><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""><div class=""><div class=""><br class=""></div>Is there any option in QE for calculating these points by just giving the high symmetry points in the input for band structure calculations.<br class=""></div></div></div></div></blockquote><div><br class=""></div>Yes, with the latest version. You can specify a k-point path as follows:</div><div><br class=""></div><div>K_POINTS { crystal_b }<br class="">5<br class="">gG 50<br class="">M 50<br class="">X 50<br class="">R 50<br class="">gG 1</div><div><br class=""></div><div>which corresponds to 5-1=4 lines in the Brillouin zone of a simple cubic lattice, that s, Gamma-M, M-X, X-R, R-Gamma, each sampled with 50 points. The point labels that are recognised are shown in detail in espresso-5.2.0/Doc/brillouin_zones.pdf</div><div><br class=""></div><div>Giovanni</div><div><br class=""></div><div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class="">Thanks,<br class=""></div>Gul <br clear="all" class=""><div class=""><div class=""><div class=""><div class=""><div class=""><div class=""><div class=""><div class=""><div class=""><div class=""><div class=""><br class="">-- <br class=""><div class=""><div dir="ltr" class=""><div class=""> </div><div style="margin: 0in 0in 0pt; line-height: normal;" class=""><span style="font-size:12pt" class=""><font color="#0000bf" class="">Dr. Gul Rahman<br class="">Assistant Professor,<br class="">Department of Physics,<br class="">Quaid-i-Azam University,<br class="">Islamabad, Pakistan</font></span></div><span style="font-size:12pt" class=""><font color="#0000bf" class=""><a href="http://www.qau.edu.pk/profile.php?id=818020" target="_blank" class="">http://www.qau.edu.pk/profile.php?id=818020</a></font></span></div></div>
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-- <br class=""><br class="">Giovanni Cantele, PhD<br class="">CNR-SPIN<br class="">c/o Dipartimento di Fisica<br class="">Universita' di Napoli "Federico II"<br class="">Complesso Universitario M. S. Angelo - Ed. 6<br class="">Via Cintia, I-80126, Napoli, Italy<br class="">e-mail: <a href="mailto:giovanni.cantele@spin.cnr.it" class="">giovanni.cantele@spin.cnr.it</a><br class="">Phone: +39 081 676910<br class="">Skype contact: giocan74<br class=""><br class="">ResearcherID: <a href="http://www.researcherid.com/rid/A-1951-2009" class="">http://www.researcherid.com/rid/A-1951-2009</a><br class="">Web page: <a href="http://people.na.infn.it/~cantele" class="">http://people.na.infn.it/~cantele</a><br class="">
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