[Wien] zigzag potential interpretation

[Peter Blaha]

Run    x lapwdm -so -up

and look at the spin and orbital moments (vectorial) of the atoms there.

Peter
On 01/03/2018 09:22 AM, Stefaan Cottenier wrote:
> Good morning Xavier,
> 
> These are the partial charges for the two different surface atoms, with 
> spin-orbit:
> 
> :CHA001: TOTAL VALENCE CHARGE INSIDE SPHERE   1 =   5.7094    (RMT=  
> 2.2200 )
> 
> :PCS001: PARTIAL CHARGES SPHERE =  1 
> S,P,D,F,PZ,PXY,,D-Z2,D-XY,D-X2Y2,D-XZ,YZ
> 
> :QTL001: 1.1585 3.0936 1.4519 0.0044 1.0202 2.0734 0.0000 0.2461 0.3659 
> 0.2540 0.5857 0.0000
> 
> :CHA002: TOTAL VALENCE CHARGE INSIDE SPHERE   2 =   5.7094    (RMT=  
> 2.2200 )
> 
> :PCS002: PARTIAL CHARGES SPHERE =  2 
> S,P,D,F,PZ,PXY,,D-Z2,D-XY,D-X2Y2,D-XZ,YZ
> 
> :QTL002: 1.1585 3.0936 1.4519 0.0044 1.0202 2.0734 0.0000 0.2461 0.3659 
> 0.2540 0.5857 0.0000
> 
> And these are the partial charges for a cell suggested by sgroup, where 
> the two surface layers are equivalent:
> 
> :CHA001: TOTAL VALENCE CHARGE INSIDE SPHERE   1 =   5.7094    (RMT=  
> 2.2200 )
> 
> :PCS001: PARTIAL CHARGES SPHERE =  1 
> S,P,D,F,PZ,PXY,,D-Z2,D-XY,D-X2Y2,D-XZ,YZ
> 
> :QTL001: 1.1585 3.0936 1.4519 0.0044 1.0202 2.0734 0.0000 0.2461 0.3659 
> 0.2540 0.5857 0.0000
> 
> As you see, there are no differences at all.
> 
> I’m confident that this result is correct, only I’m in doubt why. I 
> would understand your reasoning for a free atom: spin-orbit along 001 or 
> 00-1 would result in the same orbital occupations. No problem for a bulk 
> solid either: if you flip the moment 180 degrees, the ‘tip of the arrow’ 
> ‘sees’ the same environment in both cases. Yet I miss something for 
> these bulk slabs: in one case, the tip of the arrow sees vacuum, in the 
> other case it sees the underlying bulk. Why does that necessarily result 
> into exactly the same orbital occupations? As sgroup/initso make these 
> two surface layers equivalent, there must be a symmetry argument. And 
> it’s that one which I don’t get.
> 
> Best,
> 
> Stefaan
> 
> *Van:*Wien [mailto:wien-bounces at zeus.theochem.tuwien.ac.at] *Namens 
> *Xavier Rocquefelte
> *Verzonden:* dinsdag 2 januari 2018 21:31
> *Aan:* wien at zeus.theochem.tuwien.ac.at 
> <mailto:wien at zeus.theochem.tuwien.ac.at>
> *Onderwerp:* Re: [Wien] zigzag potential interpretation
> 
> A piece of paper will be useful to discuss this point ;)
> 
> To my point of you, the picture is correct: Fe moment point inward and 
> outward. However, I think that for a given direction (c direction) the 
> 001 and 00-1 orientation will lead to inward and outward respectively, 
> which will give the same spin moment and orbital moment. It is due to 
> the fact that the SO-effect will split the 3d orbitals similarly for the 
> 001 and 00-1 orientations. Doing two calculations with 001 and 00-1 
> magnetization direction will lead to reverse the Fe moment for a given 
> surface, and thus you will have inward and outward, respectively.
> 
> In your calculations, you have both (inward and outward) for one 
> magnetization direction due to the surface termination.
> 
> The only limitation I see here is related to the definition of the Fermi 
> level which can lead to difficulties to properly distinguish the two 
> surfaces. Would it be possible that here is the problem? Are the partial 
> DOS exactly the same?
> 
> Best Regards
> 
> Xavier
> 
> 
> 
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-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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