Dear, I appreciate your recommendation, I'll continue with these guidelines.
2017-04-17 23:57 GMT-04:00 Marton <[email protected]>: > Hi Máximo, > > 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. > > HTH > Marton Voros > > -- > Materials Science Division > Argonne National Laboratory > > On Mon, Apr 17, 2017 at 8:45 AM, Nicola Marzari <[email protected]> > wrote: > >> >> >> Indeed! At the very least, use DFT+U, and/or explore >> hybrid functionals. DFT+U+V seems to be very promising, >> but it's not in the code there. >> >> nicola >> >> >> >> On 17/04/2017 15:36, Ary Junior wrote: >> > Hi, >> > >> > Search for "constrained DFT" and you will find some documents that would >> > be useful for you, like this one >> > >> > http://theossrv1.epfl.ch/Main/OxidationStates >> > >> > Ary Ferreira >> > >> > FAPESP postdoctoral fellow >> > UFSCar - Brazil >> > >> > On Sun, Apr 16, 2017 at 1:06 PM, Máximo Ramírez <[email protected] >> > <mailto:[email protected]>> wrote: >> > >> > Dear, >> > >> > I'm interested in simulate metal oxide that has two different >> > valence state (oxidation number) in the same compound. >> > >> > For example: >> > >> > Is well-known from experimental results that spinel compounds have >> > Mn ions with valence +3 and +4, LiMn3+Mn4+O4. >> > >> > How can I simulate this behavior in QE? >> > >> > And also, How can I post-process the two atoms like were different? >> > >> > Thank in Advance! >> > >> > >> > <https://www.researchgate.net/publication/245108648_ >> Factors_affecting_Li_mobility_in_spinel_LiMn_2O_4-A_first-pr >> inciples_study_by_GGA_and_GGA_U_methods> >> > -- >> > Sincerely, >> > >> > Máximo Ramírez >> > Research Assistant >> > Nanotechnology Laboratory, INTEC >> > Santo Domingo, Dominican Republic >> > >> > >> > _______________________________________________ >> > Pw_forum mailing list >> > [email protected] <mailto:[email protected]> >> > http://pwscf.org/mailman/listinfo/pw_forum >> > <http://pwscf.org/mailman/listinfo/pw_forum> >> > >> > >> > >> > >> > -- >> > http://lattes.cnpq.br/8221674673413336 >> > >> > >> > _______________________________________________ >> > Pw_forum mailing list >> > [email protected] >> > http://pwscf.org/mailman/listinfo/pw_forum >> > >> >> -- >> ---------------------------------------------------------------------- >> Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL >> Director, National Centre for Competence in Research NCCR MARVEL, EPFL >> http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project >> _______________________________________________ >> Pw_forum mailing list >> [email protected] >> http://pwscf.org/mailman/listinfo/pw_forum >> > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
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