[Wien] Fwd:

Mon Nov 24 21:08:15 CET 2014

As I said before: lapwdm can do the job.

What I called spin-up/dn partial charges are the products
alpha*alpha and beta*beta, and their difference is Pz.

The cross-terms, leading to Px and Py are not listed individually, but
they are calculated in lapwdm, but in the output (scfdmup) summed up
over all states (and k-points).

This was what I already sent before: if you really want it for every state,
you need to run 1 k-point (lapw1 -up/dn; lapwso -up; lapw2 -so -up/dn -all emin emax;
lapwdm -up -so

and emin/emax should be set such that only ONE state at the time is occupied.

The case.scfdmup file has the info under the label   :SPIN

(but can you really forget the orbital moments ... ??   :ORB )

Am 24.11.2014 14:37, schrieb Fecher, Gerhard:
> I guess you are searching for the x and y components of the spin polarisation because usually only the z-component
> Pz = alpha alpha* - beta beta*
> is given (alpha, beta being the "up" and "down" components of a 2 component spinor, * means conjugate complex)
> the remaining two components (x and y-component) are
> Px =  2 Re(alpha beta*)   (Re = real part)
> Py = -2 Im(alpha beta*)   (Im =imaginary part)
>
> it assumed that alpha beta are normalized to alpha alpha* + beta beta* = 1, otherwise you need to divide for normalization.
>
> For wave functions that arise from a coherent superposition of spinors you should have Px^2 + Py^2 + Pz^2 = P = 1
> but not for an incoherent superposition of spinors (e.g. two spaghetti are crossing), then P may be lower than 1.
>
> if Pz is calculated somewhere in a subroutine, then it should be possible to calculate Px and Py
>
> maybe this helps you or Peter to localize the place (subroutine) to look for to answer your request.
>
> Problems will appear with the above definition if the "small" coponent of a 4 component Dirac spinor is large compared to the "large component"
>
> An old but still very good source about spin polarization is the book of J. Kessler "Polarized Electrons" (1976) from Springer  (may be it is sold out but still available online).
>
> Ciao
> Gerhard
>
> DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
> "I think the problem, to be quite honest with you,
> is that you have never actually known what the question is."
>
> ====================================
> Dr. Gerhard H. Fecher
> Institut of Inorganic and Analytical Chemistry
> Johannes Gutenberg - University
> 55099 Mainz
> and
> Max Planck Institute for Chemical Physics of Solids
> 01187 Dresden
> ________________________________________
> Von: wien-bounces at zeus.theochem.tuwien.ac.at [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von huimei liu [wwillforever at gmail.com]
> Gesendet: Montag, 24. November 2014 13:18
> An: A Mailing list for WIEN2k users
> Betreff: Re: [Wien] Fwd:
>
> If so, where can I get ul(r,E2,l) file?
> Is there any output files that can directily tell me <ψ|σ|ψ> ?
> Thank you very much!
>
> 2014-11-24 17:20 GMT+08:00 Peter Blaha <pblaha at theochem.tuwien.ac.at<mailto:pblaha at theochem.tuwien.ac.at>>:
> The error depends on how large the Blm component is. Usually it should be SMALL and therefore for an qualitative analysis negligible.
>
> However, there could be local orbitals and "Clm"s in certain cases, which could lead to errors of 100 %.
>
>
> On 11/24/2014 10:00 AM, huimei liu wrote:
>
> Dear Wien2k designers and users:
> It seems I want more than  the spin-up and dn contribution for a state.
> I 'd like to draw the spin texture.
>
> I want to calculate the spin direction for a state (k-point +
> band-index)  using the formalism <ψ|σ|ψ> to evaluate the x,y and z
> component of spin. Since I can get the Alm and Blm of the Wave function
> :ψ can be written as the sum of [Alm*ul(r)+Blm*ul'(r)]Ylm. Here is the
> question, if I use Alm only to calculate  <ψ|σ|ψ>, can I get the  close
> answer?  Or can anyone tell me the margin of error of using Alm only
> compared with using Alm and Blm toghther.
>
>
>
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>
> --
>
>                                        P.Blaha
> --------------------------------------------------------------------------
> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
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-- 
-----------------------------------------
Peter Blaha
Inst. Materials Chemistry, TU Vienna
Getreidemarkt 9, A-1060 Vienna, Austria
Tel: +43-1-5880115671
Fax: +43-1-5880115698
email: pblaha at theochem.tuwien.ac.at
-----------------------------------------