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Thanks very much for your help. I will use the sawtooth potential and see what happens. I will have another look on the band structure as well because I have done the DOS calculations and the graph seems pretty ok..<BR>
<BR>
Regards<BR>
<BR>
Elie<BR> <BR>
<HR id=stopSpelling>
Date: Wed, 29 Sep 2010 09:55:03 +0200<BR>From: sclauzer@sissa.it<BR>To: pw_forum@pwscf.org<BR>Subject: Re: [Pw_forum] Bilayer graphene with an electric field applied<BR><BR>
<META content="Microsoft SafeHTML" name=Generator>Dear Elje,<BR><BR> since you are dealing with a slab geometry and you want to apply the field along the direction perpendicular to the surface, why don't you use the sawtooth potential (tefield=.TRUE. instead of lefield=.TRUE.) to generate the E field?<BR><BR>On 09/28/2010 10:41 PM, Elie Moujaes wrote:
<BLOCKQUOTE cite=mid:SNT114-W1041A2D46423E5E7C62FF9D3660@phx.gbl>
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Dear all,<BR>I<BR>I am trying to get the band structure of graphene under the effect of an electric field. The problem is that the result at the end is very messy and jiggly. I repeated the calculations many times but I still get the same result. I first performed a scf calculation without the electric field followed by a scf calculation with an electric field and then the band calculation.<BR> <SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN></FONT></SPAN> <BR></BLOCKQUOTE><BR>Do you have some evidence that your "messy and jiggly" band structure is wrong? Are you sure that you are visualizing it in the correct way?<BR><BR><BR>HTH<BR><BR><BR>GS<BR><BR>
<BLOCKQUOTE cite=mid:SNT114-W1041A2D46423E5E7C62FF9D3660@phx.gbl> <BR>SCF with electric field<BR> <BR>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3>&control</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>prefix='bi elgraphene',</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'">pseudo_dir = '/espresso-4.2/pseudo/',</SPAN></FONT></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 = 110.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-10,<SPAN> </SPAN></FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>mixing_mode='plain'</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>efield_cart(1) = 0.0,</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>efield_cart(2) = 0.0,</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>efield_cart(3) = 0.001,</FONT></SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3><SPAN> </SPAN>startingwfc = 'random'</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>/</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-vbc.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>38 38 1<SPAN> </SPAN>0 0 0<SPAN> </SPAN></FONT></SPAN></P> <BR>I noticed that part of the bands calculation output had a problem with the convergence of one of thh eigenavalues as some of the input looked like:<BR> <BR>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'"><FONT size=3>per-process dynamical memory:<SPAN> </SPAN>30.2 Mb<BR><BR><SPAN> </SPAN>Band Structure Calculation<BR><SPAN> </SPAN>Davidson diagonalization with overlap<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged<BR><SPAN> </SPAN>c_bands:<SPAN> </SPAN>1 eigenvalues not converged</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'">Please can anyone suggest me of what could have gone wrong...</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'">Thanks</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'">Elie Moujaes</SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'">University of Nottingham</SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'">NG7 2RD</SPAN></P>
<P class=ecxMsoPlainText><SPAN lang=EN-GB style="FONT-FAMILY: 'Courier New'">UK</SPAN></P><PRE><FIELDSET class=ecxmimeAttachmentHeader></FIELDSET>
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