[Wien] Spin-polarized state not really spin-polarized

[Peter Blaha]

a) For sure, just an odd number of electrons does not mean that you have 
to have spin-polarization. If the "impurity electrons" are localized, 
magnetism is more likely, because it does not interact with neighbors 
and may form a "flat magnetic band". But the Tl-p state is certainly not 
very localized.
b) I'd start with   instgen -ask and make Pb and Te nonmagnetic, only Tl 
is kept magnetic.
c) You can try runfsm with moment=1 and compare the total energies. But 
for sure you also need to minimize forces.
d) a 64 atom cell may not yet be a good "impurity" simulation, your Tl 
concentration is 100-1000 times bigger than experiment.


Am 30.10.2022 um 13:07 schrieb pboulet:
> Dear all,
> 
> I am investigating Pb31TlTe32 in which Tl is the only element that bring 
> an odd number of electrons.
> I have set up a spin-polarized calculation with init_lapw, but not with 
> an anti-ferromagnetic state.
> As a starting point, I do not include spin-orbit and I use PBE.
> 
> NOE=959 in the structure.
> 
> After converging the SCF, I end up with the following (to me strange) 
> occupation states:
> For spin up:
> :BAN00479: 479    0.272337    0.309267  1.00000000
> :BAN00480: 480    0.283605    0.328642  0.50431432
> :BAN00481: 481    0.371927    0.455285  0.00000000
> 
> For spin down:
> :BAN00479: 479    0.272405    0.309306  1.00000000
> :BAN00480: 480    0.283720    0.328787  0.49568569
> :BAN00481: 481    0.372018    0.455369  0.00000000
> 
> I rather expected to have 480 spin up occupied states with 1 electron 
> and 479 spin down occupied states with 1 electron, but I have something 
> like a closed-shell spin polarized state.
> 
> Is it what we should expect?
> 
> If not, could you please explain me what happens and eventually how to 
> remedy this to have a ‘real’ spin polarized state?
> 
> Thank you
> Pascal
> 
> 
> Pascal Boulet
> —
> /Professor in computational materials chemistry - DEPARTMENT OF CHEMISTRY/
> University of Aix-Marseille - Avenue Escadrille Normandie Niemen - 
> F-13013 Marseille - FRANCE
> Tél: +33(0)4 13 55 18 10 - Fax : +33(0)4 13 55 18 50
> Email : pascal.boulet at univ-amu.fr <mailto:pascal.boulet at univ-amu.fr>
> 
> 
> 
> 
> 
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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