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Dear Sohail Ahmad,<br>
<br>
you need to use them in all your calculations if you want to study
the effect<br>
on the band structure... The relaxation and all calculation you do
afterward.<br>
You can of course do a quick test calculation without relaxation but
for higher<br>
fields the forces can be quite large - thus a relaxation is needed.<br>
<br>
Furthermore, if you want to simulate the E field by applying a
sawtooth<br>
potential you need to switch on the dipole correction!
dipfield=.true.<br>
Read the description in INPUT_PW.txt and also the cited paper by L.
Bengtsson<br>
<br>
PRB 59, 12301 (1999)<br>
<br>
<a class="moz-txt-link-freetext" href="http://journals.aps.org/prb/abstract/10.1103/PhysRevB.59.12301">http://journals.aps.org/prb/abstract/10.1103/PhysRevB.59.12301</a><br>
<br>
Another good paper on this subject with nice figures explaining
everything:<br>
<br>
PRB 63, 205426 (2001)<br>
<br>
<a class="moz-txt-link-freetext" href="http://journals.aps.org/prb/abstract/10.1103/PhysRevB.63.205426">http://journals.aps.org/prb/abstract/10.1103/PhysRevB.63.205426</a><br>
<br>
<br>
Regards<br>
<br>
Thomas<br>
<br>
<div class="moz-cite-prefix">On 05/07/2016 10:03 PM, Sohail Ahmad
wrote:<br>
</div>
<blockquote
cite="mid:1594159501.267420.1462651401109.JavaMail.yahoo@mail.yahoo.com"
type="cite">
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charset=windows-1252">
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font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial,
Lucida Grande, Sans-Serif;font-size:16px">
<div id="yui_3_16_0_ym19_1_1462648675723_6423">
<div id="yui_3_16_0_ym19_1_1462648675723_6508"> Dear QE user</div>
<div id="yui_3_16_0_ym19_1_1462648675723_6506">I wish to study
band gap variation after applying electric field on a
monolayer of TMDC (Lets say MoS2)</div>
<div id="yui_3_16_0_ym19_1_1462648675723_6669">My question is
.......when should i use these</div>
<div dir="ltr" id="yui_3_16_0_ym19_1_1462648675723_6683">edir
= 3, emaxpos = 0.5d0, eopreg = 0.1d0, eamp = 0.001,tefield
= .true.</div>
<div id="yui_3_16_0_ym19_1_1462648675723_6502"><b
id="yui_3_16_0_ym19_1_1462648675723_6663"><br>
</b></div>
<div id="yui_3_16_0_ym19_1_1462648675723_6691"><b
id="yui_3_16_0_ym19_1_1462648675723_6663">Do i need to
relax by using these parameters, and then use scf,nscf as
usual (without these) OR <br>
</b></div>
<div id="yui_3_16_0_ym19_1_1462648675723_6648"><b
id="yui_3_16_0_ym19_1_1462648675723_6665">Use these
paprameters directly in scf (without relax) and then
proceed as usual.</b><br>
</div>
<div id="yui_3_16_0_ym19_1_1462648675723_6645" dir="ltr"><br>
</div>
<div id="yui_3_16_0_ym19_1_1462648675723_6623" dir="ltr">Which
one of the above mentioned is correct ?</div>
<div id="yui_3_16_0_ym19_1_1462648675723_6725" dir="ltr">Anxiously
Waiting for comments</div>
<div id="yui_3_16_0_ym19_1_1462648675723_6783" dir="ltr">Best
Wishes</div>
<div id="yui_3_16_0_ym19_1_1462648675723_6837" dir="ltr">-----------------------------------------------------------------------------------------------------------------<br>
</div>
<div id="yui_3_16_0_ym19_1_1462648675723_6726" dir="ltr">Sohail
Ahmad</div>
<div id="yui_3_16_0_ym19_1_1462648675723_6838" dir="ltr">King
Khalid University <br>
</div>
<div id="yui_3_16_0_ym19_1_1462648675723_6840" dir="ltr">Abha,
Saudi Arabia<br>
</div>
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
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</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Dr. rer. nat. Thomas Brumme
Max Planck Institute for the Structure and Dynamics of Matter
Luruper Chaussee 149
22761 Hamburg
Tel: +49 (0)40 8998 6557
email: <a class="moz-txt-link-abbreviated" href="mailto:Thomas.Brumme@mpsd.mpg.de">Thomas.Brumme@mpsd.mpg.de</a>
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