<div dir="ltr"><div>Dear,<br><br></div>I appreciate your recommendation, I'll continue with these guidelines.<br></div><div class="gmail_extra"><br><div class="gmail_quote">2017-04-17 23:57 GMT-04:00 Marton <span dir="ltr"><<a href="mailto:vormar@gmail.com" target="_blank">vormar@gmail.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi Máximo,<br><br>In my experience, especially when dealing with spinel LiMn2O4, you also need to address the Jahn-Teller instability induced by Mn3+. If you slightly distort the spinel unit cell then the two different Mn sites (formally 3+ and 4+) will naturally emerge during relaxation (of course, you need the right level of theory as Nicola said): Mn3+ sites will be in a tetragonally distorted octahedral environment and Mn4+ sites will be in a more octahedral environment. If you start from a high-symmetry unit cell, you can also try to break the initial high symmetry of the charge/spin density by manually distinguishing between the two Mn sites: just name one type of Mn let's say Mn1 and the other one Mn2 and then use the same pseudopotential for both. Then, you can initialize the magnetization to a different value for the two different species.<br><div><br></div><div>HTH</div><div>Marton Voros</div><div><br></div><div>--</div><div>Materials Science Division</div><div>Argonne National Laboratory</div></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Apr 17, 2017 at 8:45 AM, Nicola Marzari <span dir="ltr"><<a href="mailto:nicola.marzari@epfl.ch" target="_blank">nicola.marzari@epfl.ch</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
<br>
Indeed! At the very least, use DFT+U, and/or explore<br>
hybrid functionals. DFT+U+V seems to be very promising,<br>
but it's not in the code there.<br>
<br>
nicola<br>
<span><br>
<br>
<br>
On 17/04/2017 15:36, Ary Junior wrote:<br>
> Hi,<br>
><br>
> Search for "constrained DFT" and you will find some documents that would<br>
> be useful for you, like this one<br>
><br>
> <a href="http://theossrv1.epfl.ch/Main/OxidationStates" rel="noreferrer" target="_blank">http://theossrv1.epfl.ch/Main/<wbr>OxidationStates</a><br>
><br>
> Ary Ferreira<br>
><br>
> FAPESP postdoctoral fellow<br>
> UFSCar - Brazil<br>
><br>
</span><span>> On Sun, Apr 16, 2017 at 1:06 PM, Máximo Ramírez <<a href="mailto:aquiles011@gmail.com" target="_blank">aquiles011@gmail.com</a><br>
</span><span>> <mailto:<a href="mailto:aquiles011@gmail.com" target="_blank">aquiles011@gmail.com</a>>> wrote:<br>
><br>
> Dear,<br>
><br>
> I'm interested in simulate metal oxide that has two different<br>
> valence state (oxidation number) in the same compound.<br>
><br>
> For example:<br>
><br>
> Is well-known from experimental results that spinel compounds have<br>
> Mn ions with valence +3 and +4, LiMn3+Mn4+O4.<br>
><br>
> How can I simulate this behavior in QE?<br>
><br>
> And also, How can I post-process the two atoms like were different?<br>
><br>
> Thank in Advance!<br>
><br>
><br>
</span>> <<a href="https://www.researchgate.net/publication/245108648_Factors_affecting_Li_mobility_in_spinel_LiMn_2O_4-A_first-principles_study_by_GGA_and_GGA_U_methods" rel="noreferrer" target="_blank">https://www.researchgate.<wbr>net/publication/245108648_<wbr>Factors_affecting_Li_mobility_<wbr>in_spinel_LiMn_2O_4-A_first-pr<wbr>inciples_study_by_GGA_and_GGA_<wbr>U_methods</a>><br>
<span>> --<br>
> Sincerely,<br>
><br>
> Máximo Ramírez<br>
> Research Assistant<br>
> Nanotechnology Laboratory, INTEC<br>
> Santo Domingo, Dominican Republic<br>
><br>
><br>
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--<br>
</span>------------------------------<wbr>------------------------------<wbr>----------<br>
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL<br>
Director, National Centre for Competence in Research NCCR MARVEL, EPFL<br>
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