<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:14pt"><div>Dear Julia,</div><div>There is just one important kpoint you shoul always pay attention to.</div><div>I have searched in your .out scf file for the following kpoint:</div><div> k = 0.3333-0.5774 0.0000 ( 9480 PWs) bands (ev):</div><div> -15.8238 -15.8238 -13.8119 <span style="color: rgb(205, 35, 44);">-3.1950 -3.1950</span> 7.4201 9.7195 9.7195</div><div style="color: rgb(205, 35, 44); font-size: 18.6667px; font-family: HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif; background-color: transparent; font-style: normal;"><span style="color: rgb(0, 0, 0);">you can find the Dirac piont here. Bit I think there is an error with your Fermi energy, because Fermi energy should be also the
same as the two energies in "red"</span><span style="color: rgb(0, 0, 0);">.</span></div><div style="color: rgb(0, 0, 0); font-size: 18.6667px; font-family: HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif; background-color: transparent; font-style: normal;"><br></div><div style="color: rgb(0, 0, 0); font-size: 18.6667px; font-family: HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif; background-color: transparent; font-style: normal;">mohammad<br></div><div style="display: block;" class="yahoo_quoted"> <br> <br> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 14pt;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt;"> <div dir="ltr"> <font face="Arial" size="2"> On Tuesday, March 11, 2014 2:08 AM, jbobak <jbobak@uvic.ca> wrote:<br> </font> </div> <div
class="y_msg_container">Hi Hadi,<br><br>Thank you so much for all the help!<br><br>Two quick questions, when you say the K-mesh is not dense enough do you<br>mean in the original SCF calculation (18x18x1) or do you mean I should<br>choose more points along the Gamma->K->M->Gamma path?<br><br>I have tried a variety of values for ecut (37, 47, 57, 67), but I have not<br>been specifying ecutrho -- why is the default value not appropriate in<br>this case? I thought 4 x ecut was ok for pseudopotentials that are not<br>ultrasoft.<br><br>Thank you again,<br>Julia<br><br>> Dear Julia,<br>><br>> They are of course in the reciprocal space no matter you want them to be<br>> or not! If your K-mesh is dense enough (which is not in your current<br>> input) and along the right paths (Which still aren't:<br>> GAMMA-to-M-to-K-to-GAMMA), then there are some parameters you need to<br>> check such as smearing/K-points/ecut/ecutrho
convergence.<br>><br>> Your smearing looks high to me and your ecut is too much for a PAW pseudo<br>> potential that you are using. Also you need to specify ecutrho as well<br>> because the default value is used in the case of norm conserving one.<br>><br>> HTH.<br>><br>> Hadi.<br>><br>> -----Original Message-----<br>> From: <a ymailto="mailto:pw_forum-bounces@pwscf.org" href="mailto:pw_forum-bounces@pwscf.org">pw_forum-bounces@pwscf.org</a> [mailto:<a ymailto="mailto:pw_forum-bounces@pwscf.org" href="mailto:pw_forum-bounces@pwscf.org">pw_forum-bounces@pwscf.org</a>] On<br>> Behalf Of jbobak<br>> Sent: 10 March 2014 18:14<br>> To: PWSCF Forum<br>> Subject: Re: [Pw_forum] Yet another question about graphene bandstructure<br>><br>> Hi Hadi,<br>><br>> Thank you for your quick response! I have tried that K-path also (I remain<br>> confused as to whether K-paths are in real or reciprocal space, so I
tried<br>> both) with a similar result.<br>><br>> Julia<br>><br>>> Dear Julia,<br>>><br>>> I guess your K-path is not entirely coincides with the high symmetry<br>>> points for graphene. Make sure you span the following routes with<br>>> enough<br>>> K:<br>>><br>>> 0 0 0<br>>> 0.666 0.333 0<br>>> 0.5 0.5 0<br>>> 0 0 0<br>>><br>>><br>>> HTH,<br>>><br>>> Hadi.<br>>> -----Original Message-----<br>>> From: <a ymailto="mailto:pw_forum-bounces@pwscf.org" href="mailto:pw_forum-bounces@pwscf.org">pw_forum-bounces@pwscf.org</a> [mailto:<a ymailto="mailto:pw_forum-bounces@pwscf.org" href="mailto:pw_forum-bounces@pwscf.org">pw_forum-bounces@pwscf.org</a>]<br>>> On Behalf Of jbobak<br>>> Sent:
10 March 2014 17:04<br>>> To: <a ymailto="mailto:pw_forum@pwscf.org" href="mailto:pw_forum@pwscf.org">pw_forum@pwscf.org</a><br>>> Subject: [Pw_forum] Yet another question about graphene bandstructure<br>>><br>>> Hi all,<br>>> I've searched the forum for this question, but nobody seems to be<br>>> having quite the same issue, so I expect I'm doing something uniquely<br>>> stupid. I am trying to calculate the band structure of graphene (using<br>>> Espresso<br>>> 5.0.3) for practice before I use a more complicated system. I do an<br>>> SCF calculation with just the unit cell (2 atoms) with automatic<br>>> k-points 18<br>>> 18 1 0 0 0. Then I do a band structure calculation with k-points as<br>>> follows:<br>>><br>>> K_POINTS {tbipa}<br>>> 7<br>>> 0.00000 0.00000 0.00000 1<br>>> 0.28868 0.16666 0.00000 1<br>>> 0.57735 0.33333 0.00000
1<br>>> 0.43301 0.41666 0.00000 1<br>>> 0.28868 0.50000 0.00000 1<br>>> 0.14435 0.25000 0.00000 1<br>>> 0.00000 0.00000 0.00000 1<br>>><br>>> I then run bands.x, followed by plotband.x which I run interactively.<br>>> Everything works fine in that I get no errors, but the bandstructure<br>>> plot is wrong (see attached pdf). The bands should cross at the K<br>>> point. I think the problem has something to do with the k-points,<br>>> which is why I have reproduced them above, but I have also attached<br>>> the relevant input and output files. Could it be because the<br>>> high-symmetry k-points I selected are not present in the automatically<br>>> selected grid?<br>>><br>>> Thank you so much for any help,<br>>> Julia Bobak<br>>><br>>> Research Assistant<br>>> University of Victoria, Victoria, BC, CANADA<br>>><br>>>
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