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<p>Hi Mouyang,</p>
<p><br>
</p>
<p>Tecnically it is ok to wannierise from a 1x1x1 when the unit cell
is big. For example, in fig 5a of this paper
<a class="moz-txt-link-freetext" href="https://iopscience.iop.org/article/10.1088/1361-648X/ab51ff/meta#cmab51fff05">https://iopscience.iop.org/article/10.1088/1361-648X/ab51ff/meta#cmab51fff05</a>
an example is shown of a 12-atom carbon chain that was wannierised
from Gamma-point only and the dispersion is restored with the MDRS
method. So, technicall Boltzwann can do the calculation even if
the wannierisation started from Gamma-point only. It will
correctly interpolate the bands to any grid of k-points and take
the derivatives.</p>
<p><br>
</p>
<p>But if it makes sense physically - is another question. The
semiclassical equations of motion (underlying the Boltzwann) are
defined for crystals. I guess the condition is that
mean-free-path is much larger then the size of the unit cell. <br>
</p>
<p><br>
</p>
<p>May be you can use the Wannier model to study quantum transport
(See chapter 7 of the user guide
<a class="moz-txt-link-freetext" href="https://raw.githubusercontent.com/wannier-developers/wannier90/v3.1.0/doc/compiled_docs/user_guide.pdf">https://raw.githubusercontent.com/wannier-developers/wannier90/v3.1.0/doc/compiled_docs/user_guide.pdf</a>)
but I am not an expert in that.</p>
<p><br>
</p>
<p>Best,</p>
<p>Stepan.<br>
</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 31.10.23 02:02, Mouyang Cheng wrote:<br>
</div>
<blockquote type="cite"
cite="mid:SA3PR01MB7987D1125DBCEACFFD8AF23ECEA0A@SA3PR01MB7987.prod.exchangelabs.com">
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Dear Stepan,<br>
<br>
Thanks for the reply, and sorry for my late response. Yes, I did
try to make the k-mesh 1*1*1 and perform the wannierlization at
this accuracy. I think my question is whether this approach
gives a reasonable tight-binding model at the DFT-level? Because
I feel strange for wannier90 only fitting one k-point for each
energy level to get so many localized wavefunctions.<br>
<br>
Another problem is that at first I tried to perform further
transport simulation in Boltzwann, but Boltzwann calculation
requires information on multiple k-points to do derivatives,
(i.e. it needs a whole band). So I guess the alternative is to
wannierlize first, then carry out tight-binding simulation on
transport by other means?<br>
<br>
Really appreciate your advice and help!<br>
<br>
Best regards,<br>
Mouyang</div>
<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>发件人:</b> Stepan
Tsirkin <a class="moz-txt-link-rfc2396E" href="mailto:stepan.tsirkin@ehu.eus"><stepan.tsirkin@ehu.eus></a><br>
<b>发送时间:</b> 2023年10月27日 20:42<br>
<b>收件人:</b> Mouyang Cheng <a class="moz-txt-link-rfc2396E" href="mailto:vipandyc@mit.edu"><vipandyc@mit.edu></a>;
<a class="moz-txt-link-abbreviated" href="mailto:wannier@lists.quantum-espresso.org">wannier@lists.quantum-espresso.org</a>
<a class="moz-txt-link-rfc2396E" href="mailto:wannier@lists.quantum-espresso.org"><wannier@lists.quantum-espresso.org></a><br>
<b>主题:</b> Re: [Wannier] Query about wannier90 calculations on
disordered supercell</font>
<div> </div>
</div>
<div>
<p>Dear Mouyang,</p>
<p><br>
</p>
<p>As I understand, there is no fundamental obstruction to make
the k-mesh 1x1x1, So you will have a Gamma-only sampling.
Although I do not have experience in that. Did you try that,
and did you come across some difficulties?</p>
<p><br>
</p>
<p>Best Regards,</p>
<p>Stepan<br>
</p>
<p><br>
</p>
<p><br>
</p>
<div class="x_moz-cite-prefix">On 26.10.23 05:15, Mouyang Cheng
wrote:<br>
</div>
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Dear Wannier90 developers,<br>
<br>
This is Mouyang Cheng, a student at MIT. I'm interested in
generating wannier orbitals for disordered systems, e.g.
amorphous 2D graphene sheet (large disorder). I've read
several articles successfully coping with applying
generalized Wannier orbitals on disordered systems like:<br>
<a
href="https://www.sciencedirect.com/science/article/abs/pii/S0038109898001756"
id="LPlnkOWALinkPreview"
class="x_OWAAutoLink x_ContentPasted0"
moz-do-not-send="true">Maximally-localized Wannier
functions for disordered systems: Application to amorphous
silicon - ScienceDirect</a>;<br>
<br>
However as to my understanding in the user manual of
Wannier90, we need to specify the Kmesh and number of bands
to do wannier fit. But for a large supercell (~200 atoms) it
is only practical for DFT to deal with only one Gamma point
for BZ, and there is no concept of band in non-crystals.<br>
<br>
<b>So my question is: can Wannier90 deal with such an
amorphous supercell and get a tight-binding Hamiltonian?
</b>If not, could you give any suggestions on any other code
or convenient methods; If yes, how does it work?<br>
<br>
Thank you so much for taking your time reading this email
and I would greatly appreciate any help or clarification.<br>
<br>
Best regards,<br>
Mouyang Cheng<br>
<br>
NSE, Massachusetts Institute of Technology<br>
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Application to amorphous silicon</a></div>
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We use the maximally-localized Wannier
function method to study bonding properties in
amorphous silicon. This study represents, to
our knowledge, the …</div>
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