[Wien] DOS over certain volume in the BZ
ebruno@unime.it
ebruno at unime.it
Wed Oct 11 21:02:48 CEST 2006
Dear Lucasz,
there are many cases in which the k-space sampling can be crucial. In
the past, Beniamino Ginatempo and I dealt with the problem and set up
a lot of staff based on adaptive grids for Brillouin zone integration
that we have used within the multiple scattering theory. The idea
there was to fix a desidered accuracy, start from an initial grid and
add new points where the variations of the integrand are too sharp. At
the end you use exactly as many k-points as you need to achieve your
accuracy goal.
The paper in which the algorithms have been described is
E. Bruno and B. Ginatempo Phys. Rev. B 55, 12946(1997)
If you like, you can reply at my e-mail that is given below.
Best wishes
Ezio
Professor Ezio Bruno
Dipartimento di Fisica
Universita' di Messina
Salita Sperone 31
98166 Messina
phone +39 090 676 5233
e-mail ebruno at unime.it
home page: http://ww2.unime.it/metallicalloys/bruno/
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Dear WIEN users,
Please see my initial question below.
Modifying tetra will be probably the last resort for me.
I would like to construct a new case.klist file using my own script,
being able to precisely control which points in the BZ are taken into
account. I understand that case.klist file contains weights for optimal
sampling of the zone using less k-points, however, I am interested in
simple cases and the number of k-points is not an issue, I could do very
dense sampling and constant weight for all points.
Also sometimes my BZ volume would be on the boundary between the first
and second BZ thus I am not really interested to work in the IBZ.
I wonder if (after running the scf cycle) I could create a new
case.klist_band file (containing dense, uniform mesh of points in the
interesting volume of BZ, e.g. sphere, cube, or cylinder), and then run
x lapw1 -band
x lapw2 -qtl -band
x tetra
to get the DOS of this volume ? Does this makes sense ?
Regards,
Lukasz
Peter Blaha wrote:
Yes, you can run first an scf cycle with a medium k-mesh, then run x
kfen and create a dense mesh and continue just with lapw2, 2,tetra
However, you will have to modify tetra to sum the DOS only over
certain tetrahedra (covering the volume you are interested in).
>> > > Hello,
>> > >
>> > > I would like to calculate the density of states over a certain volume in
>> > > the BZ. I think that it would require to sample this volume with many
>> > > k-points, i.e. prepare a new case.klist file. However, I guess that by
>> > > default the DOS utility is using the k-points which were used in the SCF
>> > > cycle.
>> > >
>> > > Would it work to create new case.klist_band, then run
>> > > x lapw1 -band
>> > > x lapw2 -qtl -band
>> > > x tetra ?
>> > >
>> > > I guess the only precaution when creating new k-list file would be to make
>> > > sure the k-point sampling is dense enough (which gets more important when
>> > > strongly dispersive bands are present in the interesting BZ volume).
>> > >
>> > > Regards,
>> > >
>> > > Lukasz
>> > >
>>
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<div class="moz-text-plain" wrap="true" graphical-quote="true"
style="font-family: -moz-fixed; font-size: 13px;" lang="x-western">Dear
WIEN users,<br>
<br>
Please see my initial question below.<br>
<br>
Modifying tetra will be probably the last resort for me.<br>
<br>
I would like to construct a new case.klist file using my own script,
being able to precisely control which points in the BZ are taken into
account. I understand that case.klist file contains weights for optimal
sampling of the zone using less k-points, however, I am interested in
simple cases and the number of k-points is not an issue, I could do
very dense sampling and constant weight for all points.<br>
<br>
Also sometimes my BZ volume would be on the boundary between the first
and second BZ thus I am not really interested to work in the IBZ.<br>
<br>
I wonder if (after running the scf cycle) I could create a new
case.klist_band file (containing dense, uniform mesh of points in the
interesting volume of BZ, e.g. sphere, cube, or cylinder), and then run
<br>
<pre wrap=""><span class="moz-txt-citetags"></span>x lapw1 -band
<span class="moz-txt-citetags"></span>x lapw2 -qtl -band
<span class="moz-txt-citetags"></span>x tetra</pre>
to get the DOS of this volume ? Does this makes sense ?<br>
<br>
Regards,<br>
<br>
Lukasz<br>
<br>
<br>
<br>
<pre wrap="">Peter Blaha wrote:
Yes, you can run first an scf cycle with a medium k-mesh, then run x
kfen and create a dense mesh and continue just with lapw2, 2,tetra
However, you will have to modify tetra to sum the DOS only over
certain tetrahedra (covering the volume you are interested in).
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap=""><span class="moz-txt-citetags">> > </span>Hello,
<span class="moz-txt-citetags">> > </span>
<span class="moz-txt-citetags">> > </span>I would like to calculate the density of states over a certain volume in
<span class="moz-txt-citetags">> > </span>the BZ. I think that it would require to sample this volume with many
<span class="moz-txt-citetags">> > </span>k-points, i.e. prepare a new case.klist file. However, I guess that by
<span class="moz-txt-citetags">> > </span>default the DOS utility is using the k-points which were used in the SCF
<span class="moz-txt-citetags">> > </span>cycle.
<span class="moz-txt-citetags">> > </span>
<span class="moz-txt-citetags">> > </span>Would it work to create new case.klist_band, then run
<span class="moz-txt-citetags">> > </span>x lapw1 -band
<span class="moz-txt-citetags">> > </span>x lapw2 -qtl -band
<span class="moz-txt-citetags">> > </span>x tetra ?
<span class="moz-txt-citetags">> > </span>
<span class="moz-txt-citetags">> > </span>I guess the only precaution when creating new k-list file would be to make
<span class="moz-txt-citetags">> > </span>sure the k-point sampling is dense enough (which gets more important when
<span class="moz-txt-citetags">> > </span>strongly dispersive bands are present in the interesting BZ volume).
<span class="moz-txt-citetags">> > </span>
<span class="moz-txt-citetags">> > </span>Regards,
<span class="moz-txt-citetags">> > </span>
<span class="moz-txt-citetags">> > </span>Lukasz
<span class="moz-txt-citetags">> > </span>
</pre>
</blockquote>
</blockquote>
<pre wrap=""><!---->
</pre>
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