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<div class="moz-cite-prefix">Dear Ghadiyali Mohammed Kader,<br>
<br>
the paper by Meyer and Vanderbilt is fine - no use to read the one
by Bengtsson.<br>
In general, you can apply an electric field using the sawtooth
potential in every<br>
system with at least one non-periodic direction. Note that you
need to place the<br>
potential jump (i.e., the dipole which is used to model the
electric field) in the<br>
vacuum region, and the field along a non-periodic direction...<br>
In the case of your nanoribbon this would be the x- and
y-direction. Usually, you<br>
also need to switch on the dipole correction (dipfield = .true.).<br>
<br>
Regards<br>
<br>
Thomas<br>
<br>
On 08.01.2018 11:49, Mohammed Ghadiyali wrote:<br>
</div>
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<p style="margin-top:0;margin-bottom:0">Respected Sir,</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">Thanks for the
information.</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">Actually, I had checked
this paper: <span>Meyer and Vanderbilt, PRB 63, 205426 (2001)</span></p>
<p style="margin-top:0;margin-bottom:0">And was not able to find
any details regarding the parallel field, I would read the
other paper as well, thanks for the reference.</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">I do have an additional
question, is it possible to apply an electric field to a
nanoribbon, like a graphene nanoribbon, which has vacuum on
two axis, I have attached an input.</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0"><span style="font-size:
12pt;">Regards,</span><br>
</p>
<p style="margin-top:0;margin-bottom:0">Ghadiyali Mohammed
Kader.</p>
Research Scholar,
<div>Dept. of Physics,</div>
<div>University of Mumbai.<br>
<br>
<div style="color: rgb(0, 0, 0);">
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font
style="font-size:11pt" face="Calibri, sans-serif"
color="#000000"><b>From:</b> Thomas Brumme
<a class="moz-txt-link-rfc2396E" href="mailto:thomas.brumme@uni-leipzig.de"><thomas.brumme@uni-leipzig.de></a><br>
<b>Sent:</b> Monday, January 8, 2018 4:00 PM<br>
<b>To:</b> Mohammed Ghadiyali; PWSCF Forum<br>
<b>Subject:</b> Re: [Pw_forum] Applying sawtooth filed
parallel to a system</font>
<div> </div>
</div>
<div style="background-color:#FFFFFF">Dear Ghadiyali
Mohammed Kader,<br>
<br>
there was no input file attached to your mail. Anyway...
The electric field via "tefield"<br>
can only be used in systems where you have a vacuum region
in which you can place<br>
the potential jump. Maybe you should have a look at, e.g.,<br>
<br>
L. Bengtsson, Phys. Rev. B 59, 12301 (1999)<br>
<br>
to understand what this method is about. If you want to
apply an electric field via the<br>
modern theory of the polarization have a look at the input
variable "lelfield" and<br>
example 4 of PW.<br>
<br>
Regards<br>
<br>
Thomas<br>
<br>
<div class="x_moz-cite-prefix">On 08.01.2018 11:17,
Mohammed Ghadiyali wrote:<br>
</div>
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style="font-size:12pt; color:#000000;
font-family:Calibri,Helvetica,sans-serif">
<p style="margin-top:0; margin-bottom:0">Respected
Sir,</p>
<p style="margin-top:0; margin-bottom:0"><br>
</p>
<p style="margin-top:0; margin-bottom:0">Thanks for
the input.</p>
<p style="margin-top:0; margin-bottom:0"><br>
</p>
<p style="margin-top:0; margin-bottom:0">But, if one
is dealing with a bulk system with no vacuum then
the potential jump would be in the system?</p>
<p style="margin-top:0; margin-bottom:0"><br>
</p>
Regards,
<div>Ghadiyali Mohammed Kader,</div>
<div>Research Scholar,</div>
<div>Dept. of Physics,</div>
<div>University of Mumbai.</div>
<div><br>
<div style="color:rgb(0,0,0)">
<hr style="display:inline-block; width:98%"
tabindex="-1">
<div id="x_divRplyFwdMsg" dir="ltr"><font
style="font-size:11pt" face="Calibri,
sans-serif" color="#000000"><b>From:</b>
Thomas Brumme
<a class="x_moz-txt-link-rfc2396E"
href="mailto:thomas.brumme@uni-leipzig.de"
moz-do-not-send="true"><thomas.brumme@uni-leipzig.de></a><br>
<b>Sent:</b> Monday, January 8, 2018 3:33 PM<br>
<b>To:</b> PWSCF Forum; Mohammed Ghadiyali<br>
<b>Subject:</b> Re: [Pw_forum] Applying
sawtooth filed parallel to a system</font>
<div> </div>
</div>
<div style="background-color:#FFFFFF">Dear
Ghadiyali Mohammed Kader,<br>
<br>
applying the electric field parallel to the
system, thus placing the potential jump "into"
the system<br>
makes no sense and is wrong. Yet, if you provide
more details on what you actually want to do,<br>
someone might be able to help.<br>
<br>
Regards<br>
<br>
Thomas<br>
<br>
<div class="x_x_moz-cite-prefix">On 08.01.2018
08:05, Mohammed Ghadiyali wrote:<br>
</div>
<blockquote type="cite">
<div id="x_x_divtagdefaultwrapper" dir="ltr"
style="font-size:12pt; color:#000000;
font-family:Calibri,Helvetica,sans-serif">
<p style="margin-top:0; margin-bottom:0">Dear
All,</p>
<p style="margin-top:0; margin-bottom:0"><br>
</p>
<p style="margin-top:0; margin-bottom:0">Is
it possible to use the sawtooth method as
I require smearing for applying electric
field parallel to a system?</p>
<p style="margin-top:0; margin-bottom:0"><br>
</p>
<p style="margin-top:0; margin-bottom:0">I
do understand the parameter edir can be
used to specify the direction, but it also
specifies the direction of vacuum.</p>
<p style="margin-top:0; margin-bottom:0">I
mean, I have a vacuum along the
z-direction and I want to apply the
electric field along the x and
y-direction. </p>
<p style="margin-top:0; margin-bottom:0">Then
how to select the values of emoxpos and <span>eopreg?</span></p>
<p style="margin-top:0; margin-bottom:0"><span><br>
</span></p>
<p style="margin-top:0; margin-bottom:0"><span>Regards,</span></p>
<p style="margin-top:0; margin-bottom:0"><span>Ghadiyali
Mohammed Kader,</span></p>
<p style="margin-top:0; margin-bottom:0"><span>Research
Scholar,</span></p>
<p style="margin-top:0; margin-bottom:0">Dept.
of Physics,</p>
<p style="margin-top:0; margin-bottom:0">University
of Mumbai.</p>
<p style="margin-top:0; margin-bottom:0"><br>
</p>
</div>
<br>
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<pre class="x_x_moz-signature" cols="72">--
Dr. rer. nat. Thomas Brumme
Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry
Leipzig University
Phillipp-Rosenthal-Strasse 31
04103 Leipzig
Tel: +49 (0)341 97 36456
email: <a class="x_x_moz-txt-link-abbreviated" href="mailto:thomas.brumme@uni-leipzig.de" moz-do-not-send="true">thomas.brumme@uni-leipzig.de</a>
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<br>
<pre class="x_moz-signature" cols="72">--
Dr. rer. nat. Thomas Brumme
Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry
Leipzig University
Phillipp-Rosenthal-Strasse 31
04103 Leipzig
Tel: +49 (0)341 97 36456
email: <a class="x_moz-txt-link-abbreviated" href="mailto:thomas.brumme@uni-leipzig.de" moz-do-not-send="true">thomas.brumme@uni-leipzig.de</a>
</pre>
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</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Dr. rer. nat. Thomas Brumme
Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry
Leipzig University
Phillipp-Rosenthal-Strasse 31
04103 Leipzig
Tel: +49 (0)341 97 36456
email: <a class="moz-txt-link-abbreviated" href="mailto:thomas.brumme@uni-leipzig.de">thomas.brumme@uni-leipzig.de</a>
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