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<p>Hi </p>
<p> the starting_magnetization is specified per species not per
site, this may be sometime not very practical, but in your case
warrants that the supercell is initialized in the same way as
the bulk one. Consider also that if the ferromagnetic solution is
stable, the final density and magnetization are not very sensitive
to the specific initialization, the starting_magnetization only
breaks the symmetry between the two polarization and defines which
is the majority spin. <br>
</p>
<p>Contrains instead affect the energy with an additive term that
depends on the deviation from the constaint, and as you are going
to do finite differences between displaced systems, where you
might actually expect some small variation of the local
magnetizations this could influence you results. <br>
</p>
<p>hope this helps - regards <br>
</p>
<p>Pietro<br>
</p>
<div class="moz-cite-prefix">On 28/07/20 00:35, Hien Vo wrote:<br>
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<p class="MsoNormal">Hi all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m trying to compute phonons by the frozen
phonon approach of a ferromagnetic system. I’m not exactly
sure how to go about it. <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m planning to converge a unit cell of 20
atoms using the starting_magnetization option. Then I will use
Phonopy to generate a set of 80-atom supercells with finite
displacements and run pwscf on those. How should I treat
magnetization in these supercells? I’m concerned that if I use
starting_magnetization again, the systems might converge to
different ‘magnetic moment per site’ values. <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m thinking of trying the
constrained_magnetization=’atomic’ option and constrain each
atomic magnetic moment to the value achieved in the 20-atom
unit cell. Is this the way to go? <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best,<o:p></o:p></p>
<p class="MsoNormal">Hien Vo<o:p></o:p></p>
<p class="MsoNormal">PhD Student<o:p></o:p></p>
<p class="MsoNormal">Chemistry Department | The University of
Chicago <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hien Vo<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<br>
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