<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div><div>Dear Fariba,</div><div><br></div><div> why do you write me directly? I never performed electronic structure calculations on graphite, writing to the PWforum you would have more chance to get useful answers. Moreover other users could benefit from the discussion...</div><div><br></div><div>At first glance your input file looks fine. I don't know about the literature on this topic, but you should be aware that typically band gaps do not come out very well within LDA, and for some cases even GGA does not good job (e.g. transition metal oxides). Honestly, I don't know how well LDA/GGA describe graphene nanoribbons.</div><div><br></div><div>What I can suggest is to check convergence with ecutwfc, degauss, ... if you haven't done yet. Maybe try other PPs.</div><div><br></div><div>Regards</div><div><br></div><div>Gabriele</div><br><div><div>Il!
giorno 04/mag/09, alle ore 12:59, <a href="mailto:nazari@iasbs.ac.ir">nazari@iasbs.ac.ir</a> ha scritto:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div><br> Dear Gabriele Sclauzero,<br><br> I wish to get the band structure and band gap for graphene nanoribbon.<br><br> In the attachemnt you can find the input for 2*2 graphene nanoribbon and<br><br> relatetd band structure. In litrature the reported band gap for such<br><br> structure is in the range of 0.5-0.6. I get such value for small number<br><br> of k-point but by increasing the number of kpoint the band gap decrases<br><br> and this not compatible with litratue. Would you please have look to<br><br> input and let me know if there exist a problem.<br><br> regards<br> Fariba nazari<br> IASBS<span><G1.pdf></span></div></blockquote></div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size:!
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lass="Apple-interchange-newline"><br class="Apple-interchange-newline"><font class="Apple-style-span" color="#7E7E7E">Gabriele Sclauzero, PhD Student</font></i></div><div><i><font class="Apple-style-span" color="#7E7E7E"> SISSA & CNR-INFM Democritos,</font></i></div><div><i><font class="Apple-style-span" color="#7E7E7E"> via Beirut 2-4, 34014 Trieste (Italy)</font></i></div><div><i><font class="Apple-style-span" color="#7E7E7E"> email: <a href="mailto:sclauzer@sissa.it">sclauzer@sissa.it</a> </font></i></div><div><i><font class="Apple-style-span" color="#7E7E7E"> phone: +39 040 3787 511</font></i></div><div><i><font class="Apple-style-span" color="#7E7E7E"> skype: gurlonotturno</font></i></div><div><br></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"> </div><br></body></html>