[Wien] Spin-polarized state not really spin-polarized
xavier rocquefelte
xavier.rocquefelte at univ-rennes1.fr
Sun Oct 30 17:31:07 CET 2022
Dear Pascal,
I think that in such a case you definitely need to include the
spin-orbit coupling to insure that the bands will be properly treated
near the Fermi energy, for instance.
Indeed, in the lift of the degeneracies spin-orbit will be significant
and can really play a role in stabilizing a specific spin configuration.
I will not go towards runfsm, but I will first try to define a starting
point with no magnetic moments on the expected "non-magnetic elements".
Experimentally Pb31TlTe32 is metallic or semiconductor?
Best regards
Xavier
On 30/10/2022 16:30, pboulet wrote:
> All right, so here are the MMTOT data:
>
> Starting point of SCF: 123.85779
> Converged: 0.05631
>
> And MMI ones:
> Starting point:
> :MMINT: MAGNETIC MOMENT IN INTERSTITIAL = 71.11022
> :MMI001: MAGNETIC MOMENT IN SPHERE 1 = 1.03742
> :MMI002: MAGNETIC MOMENT IN SPHERE 2 = 1.03736
> :MMI003: MAGNETIC MOMENT IN SPHERE 3 = 0.62202
> :MMI004: MAGNETIC MOMENT IN SPHERE 4 = 0.62205
> :MMI005: MAGNETIC MOMENT IN SPHERE 5 = 1.03746
> :MMI006: MAGNETIC MOMENT IN SPHERE 6 = 0.62203
> :MMI007: MAGNETIC MOMENT IN SPHERE 7 = 0.62196
> :MMI008: MAGNETIC MOMENT IN SPHERE 8 = 1.03238
> :MMI009: MAGNETIC MOMENT IN SPHERE 9 = 0.62236
> :MMI010: MAGNETIC MOMENT IN SPHERE 10 = 0.29692
>
> Converged:
> :MMINT: MAGNETIC MOMENT IN INTERSTITIAL = 0.04102
> :MMI001: MAGNETIC MOMENT IN SPHERE 1 = 0.00000
> :MMI002: MAGNETIC MOMENT IN SPHERE 2 = -0.00015
> :MMI003: MAGNETIC MOMENT IN SPHERE 3 = 0.00028
> :MMI004: MAGNETIC MOMENT IN SPHERE 4 = 0.00029
> :MMI005: MAGNETIC MOMENT IN SPHERE 5 = -0.00003
> :MMI006: MAGNETIC MOMENT IN SPHERE 6 = 0.00030
> :MMI007: MAGNETIC MOMENT IN SPHERE 7 = 0.00027
> :MMI008: MAGNETIC MOMENT IN SPHERE 8 = 0.00104
> :MMI009: MAGNETIC MOMENT IN SPHERE 9 = 0.00038
> :MMI010: MAGNETIC MOMENT IN SPHERE 10 = 0.00128
>
> Obviously the system converges towards a non-spin polarized state.
>
> From the literature, there has been some experimental investigation
> on, e.g., Pb(1-x)Tl(x)Te (x=0.001-0.02). One can read: [..] Various
> mechanisms** which can lead to observable anomalies, including
> Kondo-like behavior of a *non-magnetic degenerate two-level system*
> are discussed.
>
> So maybe the structure is non-magnetic.
>
> ** related to thermoelectric power
>
> Now let’s say I want to make sure this is a non-magnetic compound by
> enforcing a magnetic state (in which case the total energy should be
> higher than for the non-magnetic state), I should run runfsm_lapw and
> change case.inst to enforce a spin polarization right at the
> beginning, shouldn’t I?
>
>
> Pascal
>
>
>
>> Le 30 oct. 2022 à 14:04, fabien.tran at vasp.at a écrit :
>>
>> Dear Pascal,
>>
>> Depending on the system it may be possible to stabilize more than one
>> magnetic state. In such cases, the magnetic state obtained at the end
>> of the calculation typically depends on the initial magnetic state
>> when starting the calculation. What was the initial magnetic state in
>> your calculation? Grep for :MMTOT (total moment in cell) or :MMI
>> (moment on atoms) in case.scf to see how these quantities evolved
>> during the SCF procedure. Is Pb31TlTe32 supposed to be magnetic
>> according to experiment?
>>
>> On 30.10.2022 13:07, pboulet wrote:
>>> 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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>
> 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
>
>
>
>
>
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--
------------------------
Professeur des Universités de Rennes 1
Institut des Sciences Chimiques de Rennes (ISCR)
Univ Rennes - CNRS - UMR6226, France
https://iscr.univ-rennes1.fr/xavier-rocquefelte
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