<div dir="ltr"><div><div>Since the mentioned problem with graphene arises more often than not, I put an example of input data for graphene here: <a href="http://www.quantum-espresso.org/faq/input-data/#3.8" target="_blank">http://www.quantum-espresso.org/faq/input-data/#3.8</a><i> (</i>I hope nobody will take offence for the joke in  <a href="http://www.quantum-espresso.org/faq/self-consistency/#6.15" target="_blank">http://www.quantum-espresso.org/faq/self-consistency/#6.15</a>: it actually took me some time to get both the atomic positions and the k-point list right).<br></div><br></div>Paolo<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Nov 23, 2015 at 12:24 PM, Hildebrand, Mariana <span dir="ltr"><<a href="mailto:mariana.hildebrand13@imperial.ac.uk" target="_blank">mariana.hildebrand13@imperial.ac.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">



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<div style="word-wrap:break-word">Dear all,
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<div>I know there have been loads of posts about this topic before and I looked through them for the past 2 weeks.</div>
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<div>In the course of my PhD (which I just started) I am looking at band gap tuning in graphene. So I just benchmarked graphene (cutoff energy, k-point,</div>
<div>optimisation of lattice parameter etc) and now attempt to calculate the band structure.</div>
<div>However, I constantly obtain a band gap when I should see the characteristic Dirac point in K. So I checked if I use enough vacuum space, enough k-points, how the pseudopotential influences the band structure, which unit cell/lattice vectors quantum
 espresso is using so that I give the high symmetry points in the correct positions (I tried different positions for the high symmetry points) and also used the k-point path generator of xcrysden (the k-point path obtained with that is used in the input files
 I attached).</div>
<div>I should mention that I use the following script for the generation of band structures and have successfully used it before on Au(111) surfaces:</div>
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<div><a href="http://www.tcm.phy.cam.ac.uk/~jry20/bands.html" target="_blank">http://www.tcm.phy.cam.ac.uk/~jry20/bands.html</a></div>
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<div>As already mentioned, please find my latest in and output files as well as the script and README file for the script I am using to generate band structures with quantum espresso in the following shared dropbox folder:</div>
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<div><a href="https://www.dropbox.com/sh/gtq8djtsew5h573/AABTzcqWMJ5iR9UMiTzEDFUYa?dl=0" target="_blank">https://www.dropbox.com/sh/gtq8djtsew5h573/AABTzcqWMJ5iR9UMiTzEDFUYa?dl=0</a></div>
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<div>Best wishes,</div>
<div>Mariana Hildebrand.</div>
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<br>_______________________________________________<br>
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<a href="http://pwscf.org/mailman/listinfo/pw_forum" rel="noreferrer" target="_blank">http://pwscf.org/mailman/listinfo/pw_forum</a><br></blockquote></div><br><br clear="all"><br>-- <br><div class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><span><span><font color="#888888">Paolo Giannozzi, Dept. Chemistry&Physics&Environment,<br>
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>
Phone <a href="tel:%2B39-0432-558216" value="+390432558216" target="_blank">+39-0432-558216</a>, fax <a href="tel:%2B39-0432-558222" value="+390432558222" target="_blank">+39-0432-558222</a></font></span></span></div></div></div></div>
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