<html>
<head>
<style><!--
.hmmessage P
{
margin:0px;
padding:0px
}
body.hmmessage
{
font-size: 10pt;
font-family:Tahoma
}
--></style>
</head>
<body class='hmmessage'>
Dear Prof. Eyvaz,<BR>
<BR>
Thanks a lot for the information. Everything is solved now..<BR>
<BR>
Elie<BR> <BR>
<HR id=stopSpelling>
Date: Tue, 14 Dec 2010 13:40:59 -0800<BR>From: eyvaz_isaev@yahoo.com<BR>To: pw_forum@pwscf.org<BR>Subject: Re: [Pw_forum] Bilayer graphene subject to an electric field<BR><BR>
<META content="Microsoft SafeHTML" name=Generator>
<STYLE>
.ExternalClass DIV
{;}
</STYLE>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman,new york,times,serif">Hi,<BR><BR>A couple of comments that might be useful.<BR><BR>1. As you use an US pseudopotential, reduce ecutwfc down to ~30Ry. I do not see any reason for such kind of high cutoff energy, unless you performed some tests and proved that 60Ry is better. Besides, for the same reason (US PsP), you should use more ecutrho (8-12 times of ecutwfc). By default ecutrho=4*ecutwfc (why so, think about) and this works for norm-conserving PsPs. <BR><BR>As a reference see N.Mounet and N. Marzari, Phys. Rev. B 71, 205214 (2005), where they used ecutoff=40Ry for graphene and other C-based structures.<BR><BR>2. I have noticed that the job started to converge when I used smaller efield_cart(3)=0.05, after 49 iteration I had<BR><BR> estimated scf accuracy < 0.00007068 Ry<BR><BR>but then my notebook turned off due to a heating problem, I suggest. As I just tried to test the problem I used only 2x2x1 k-points set, and mixing_beta(1)=0.05. <BR>But when I used efield_cart(3)=0.005 (with mixing coefficient 0.1) the job finished after 11 iterations. <BR>
<DIV><BR>Hope this helps.<BR><BR>Bests,<BR>Eyvaz. <BR>-------------------------------------------------------------------<BR></DIV>Prof. Eyvaz Isaev, <BR>Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden <BR>Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, <BR>isaev@ifm.liu.se, eyvaz_isaev@yahoo.com
<DIV><BR></DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman,new york,times,serif"><BR>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman,new york,times,serif"><FONT face=Tahoma size=2>
<HR SIZE=1>
<B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B> Elie Moujaes <elie.moujaes@hotmail.co.uk><BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> pw_forum@pwscf.org<BR><B><SPAN style="FONT-WEIGHT: bold">Sent:</SPAN></B> Mon, December 13, 2010 1:57:36 PM<BR><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B> [Pw_forum] Bilayer graphene subject to an electric field<BR></FONT><BR>
<STYLE>
.ExternalClass .ecxhmmessage P
{padding:0px;}
.ExternalClass body.ecxhmmessage
{font-size:10pt;font-family:Tahoma;}
</STYLE>
<FONT size=3>Dear all,</FONT><BR><FONT size=3></FONT> <BR><FONT size=3>I am trying to get the band structure of bilayer graphene under the effect of an external electric field. I have done the scf calculations without the inclusion of an electric field , then again did teh scf calculation with an electric field included in the z-direction (of value 0.1 Ry). However the convergence is not achieved and it stopped after 100 iterations giving the following message:</FONT><BR> <BR> <BR>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>total cpu time spent up to now is<SPAN> </SPAN>83435.11 secs<BR><BR><SPAN> </SPAN>total energy<SPAN> </SPAN>=<SPAN> </SPAN>-52.83248336 Ry<BR><SPAN> </SPAN>Harris-Foulkes estimate<SPAN> </SPAN>=<SPAN> </SPAN>-45.80937450 Ry<BR><SPAN> </SPAN>estimated scf accuracy<SPAN> </SPAN>< <SPAN> </SPAN>0.00524127 Ry<BR><BR><SPAN> </SPAN>End of self-consistent calculation<BR><BR><SPAN> </SPAN>convergence NOT achieved after 100 iterations: stopping</FONT><BR></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"></SPAN> </P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT style="FONT-SIZE: 12pt" face=Tahoma size=3>You will find below the inout file for the scf calculation when an electric field is applied:</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT face=Tahoma size=3></FONT></SPAN> </P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT face=Tahoma size=3></FONT></SPAN> </P><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'">
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>&control</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>prefix='bielgraphene',</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>calculation='scf',</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>restart_mode='from_scratch',</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>lelfield = .true.,</FONT></SPAN></P>
<P class=ecxMsoPlainText><FONT size=3><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><SPAN> </SPAN></SPAN><SPAN lang=PT-BR style="FONT-FAMILY: 'Courier New'">nberrycyc= 1,</SPAN></FONT></P>
<P class=ecxMsoPlainText><SPAN lang=PT-BR style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>pseudo_dir = '/espresso-4.2/pseudo/',</FONT></SPAN></P>
<P class=ecxMsoPlainText><FONT size=3><SPAN lang=PT-BR style="FONT-FAMILY: 'Courier New'"><SPAN> </SPAN></SPAN><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'">outdir='/tmp/results_MOUJAES/'</SPAN></FONT></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>/</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>&system<SPAN> </SPAN></FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>ibrav=<SPAN> </SPAN>4, celldm(1) =4.608737, celldm(3)=5.330410, nat=4, ntyp= 1,</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>ecutwfc = 60.D0,occupations='smearing',smearing='methfessel-paxton', degauss=0.01</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3>/</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>&electrons</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>conv_thr=1.D-5,<SPAN> </SPAN></FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>mixing_mode='local-TF'</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>mixing_beta=0.1D0</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>efield_cart(1) = 0.000,</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>efield_cart(2) = 0.000,</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>efield_cart(3) = 0.10,</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN></FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>/</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3>ATOMIC_SPECIES</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>C<SPAN> </SPAN>12.0107<SPAN> </SPAN>C.pz-rrkjus.UPF</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3>ATOMIC_POSITIONS crystal</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>C 0.000000<SPAN> </SPAN>0.000000<SPAN> </SPAN>0.000000<SPAN> </SPAN></FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>C 0.000000<SPAN> </SPAN>0.000000<SPAN> </SPAN>0.257692 </FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>C 0.333333<SPAN> </SPAN>-0.33333<SPAN> </SPAN>0.000000<SPAN> </SPAN></FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>C -0.333333<SPAN> </SPAN>0.33333<SPAN> </SPAN>0.257692<SPAN> </SPAN></FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3> </FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3>K_POINTS automatic</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>25 25 1<SPAN> </SPAN>0 0 0<SPAN> </SPAN></FONT></SPAN></P>
<P class=ecxMsoPlainText> </P>
<P class=ecxMsoPlainText> </P>
<P class=ecxMsoPlainText><FONT face=Tahoma size=3>Thanks</FONT></P>
<P class=ecxMsoPlainText><FONT face=Tahoma size=3></FONT> </P>
<P class=ecxMsoPlainText><FONT face=Tahoma size=3>Elie Moujaes</FONT></P>
<P class=ecxMsoPlainText><FONT face=Tahoma size=3>University of Nottingham</FONT></P>
<P class=ecxMsoPlainText><FONT face=Tahoma size=3>NG7 2RD</FONT></P>
<P class=ecxMsoPlainText><FONT face=Tahoma size=3>UK</FONT></P></SPAN></DIV></DIV></DIV><BR><BR>_______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum </body>
</html>