[Wien] magnetizatin direction in case.inso vs case.inst

[pluto]

Dear Prof. Blaha,

Thank you for your support!

Best,
Lukasz


On 2024-10-13 13:20, Peter Blaha wrote:
> Yes, it is arbitrary what to specify up/dn in case.inst and you can 
> swap it.
> 
> The orbital moment is just the sum_l ( sum_m ( m . q_lm ))
> 
> In other words: for a TM, you check the m=-2, -1, 0,1,2  partial
> charges, multiply it with the corresponding m and sum up.
> 
> 
> Am 13.10.2024 um 12:35 schrieb pluto via Wien:
>> Dear Prof. Blaha,
>> 
>> Thank you for very quick answer!
>> 
>> I understand that once I set the magnetization to [001] in case.inso, 
>> then the majority-spin will be aligned along [001].
>> 
>> This means that when I use instgen_lapw, every local moment that I set 
>> to "up" will be initially aligned along [001], and every local moment 
>> that I set to "dn" will be aligned along [00-1].
>> 
>> I understand that this initial configuration can change over the SCF 
>> cycles, but one can monitor this using "grep :MM case.scf".
>> 
>> I understand that the orbital moment is just a consequence of the 
>> above settings.
>> 
>> I have two follow-up questions:
>> 
>> - Is the direction of the majority/minority spin in instgen_lapw 
>> arbitrary? This would mean swapping all up/dn there would also 
>> effectively swap the directions of local moments along the M direction 
>> set in case.inso
>> 
>> - How is the orbital moment calculated?
>> 
>> Best,
>> Lukasz
>> 
>> PS: Some output of my converged calculation below. Sphere 1 is "up", 
>> sphere 2 is "dn", other spheres are non-magnetic. Orbital moment seems 
>> quite significant.
>> 
>> grep :MM case.scf
>> :MMINT:  MAGNETIC MOMENT IN INTERSTITIAL  =    0.69969
>> :MMI001: MAGNETIC MOMENT IN SPHERE   1    =    5.16649
>> :MMI002: MAGNETIC MOMENT IN SPHERE   2    =   -2.41664
>> :MMI003: MAGNETIC MOMENT IN SPHERE   3    =    0.10539
>> :MMI004: MAGNETIC MOMENT IN SPHERE   4    =    0.10587
>> :MMI005: MAGNETIC MOMENT IN SPHERE   5    =    0.11216
>> :MMTOT:  SPIN MAGNETIC MOMENT IN CELL     =   -7.98682
>> 
>> grep :ORB case.scf
>> :ORB001:  ORBITAL MOMENT:  0.00000  0.00000  1.62857 PROJECTION ON M 
>> 1.62857
>> 
>> 
>> 
>> 
>> On 2024-10-13 09:36, Peter Blaha wrote:
>>> Many "No.no.no" ..., see below.
>>> 
>>>> I would like to make a collinear magnetic+SOC calculation that 
>>>> simulates the sample magnetized in opposite directions along some 
>>>> easy axis. I am looking both at ferromagnetic and ferrimagnetic 
>>>> samples, where only some atoms are magnetic. Could you please tell 
>>>> me the correct procedure.
>>>> 
>>>> One can set the direction of magnetization in case.inso and in 
>>>> case.inst.
>>> 
>>> No, only in case.inso.
>>> Without SO, there is no coupling of the direction of the magnetic
>>> moment and the lattice.
>>> What you set in case.insp is the STARTING (can change during scf)
>>> SPIN-magnetic moment. But "up" means just "majority", and does NOT
>>> mean a "z-direction" with respect to your lattice.
>>> 
>>> 
>>>> One can see sizes of magnetic moments through:
>>>> 
>>>> grep :MM case.scf
>>> 
>>> These are only the spin-moments. In a SO calculation, you should add
>>> the orbital moments (check your scf file).
>>> 
>>> You can then also check the direction of the moments with respect to
>>> your quantization axis in case.inso.
>>> 
>>> I guess the above shoud have answered also the rest of your 
>>> questions.
>>> 
>>>> 
>>>> How are all the three things (inso, inst, and scf) related?
>>>> 
>>>> I would assume that case.inso only sets the quantization axis (but 
>>>> does not physically change the directions of magnetic moments). 
>>>> Therefore, for two identical calculations but with inso at [001] and 
>>>> [00-1], the result should be exactly the same in energy, but the 
>>>> spin up/dn weights of orbital characters should be swapped. Spin- 
>>>> integrated (adding up+dn) weights of the Ylm orbitals should not 
>>>> change in such case.
>>>> 
>>>> But then what is the precise meaning of the u/d/n when producing the 
>>>> case.inst using instgen_lapw? Are those, for the SOC calculation, 
>>>> ultimately referring to the quantization axis set in case.inso? I 
>>>> mean, would setting "up" in case.inst mean the moment oriented in 
>>>> real space along the direction set by instgen_lapw in case.inso?
>>>> 
>>>> Also, what do the magnetic moments in case.scf mean? They have 
>>>> signs, so they must refer to some quantization axis.
>>>> 
>>>> Best,
>>>> Lukasz
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