[Wien] Optical properties with SO coupling

Fecher, Gerhard fecher at uni-mainz.de
Thu Oct 5 15:14:38 CEST 2017 

Hi Jaroslav,
if you check only case.jointup it has possibly only half the value because the other half is supposed to be in case.jointdn
(with SO they should be the same)

Did you try to copy case.jointup to case.jointdn (or run in addition everything for dn)
and then addjoint
then the factor 2 is included in the case.joint

The problem with spinpolarisation and SO is that case.jointup is the only necessary and produced, however, kram expects that case.joint exists
that's why one has to do the copy by hand (not rename, then the factor 2 will be missing, again !)
(one might also run optic and joint both in addition for dn, before addjoint)

Indeed, it would be nice if this behaviopur could be changed (maybe by some switch(es) to kram : e.g.: -so -up)




Just for curiosity, I wonder whether and how crossterms are respected, the selcction rules on the total angular momentum j' = j, j+-1 together with those on the magnetic quantum number mj
allow spin flip transitions even though the dipole operator does not act on the spin !

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 [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von Jaroslav Hamrle [hamrle at karlov.mff.cuni.cz]
Gesendet: Donnerstag, 5. Oktober 2017 09:57
An: wien at zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] Optical properties with SO coupling

Dear Gavin,

I will describe my observation:
I have calculated optical (epzz) and magneto-optical (K, for example K=epxy for M001) spectra of permittivity elements for bcc Fe.
The electronic structure calculations are spin polarized, with spin-orbit, run by commands:

runsp_lapw -p
runsp_lapw -p -so -cc 0.000001 -ec 0.0000001 -s lapw1
x lapw2 -p -fermi -up -so
x optic -p -up -so
x joint -p -up

For w2k version 16.1, the calculated spectra corresponds to the experimental spectra (for both epzz and K).
For w2k version 17.1, the calculated spectra are half-value for both epzz and K, compared to the experiment.

Figures comparing spectra are here:

http://alma.karlov.mff.cuni.cz/hamrle/w2kfig/Fe_Imepzz_compare.pdf
http://alma.karlov.mff.cuni.cz/hamrle/w2kfig/Fe_ReK_compare.pdf

In this example, I used permittivity spectra read directly from case.jointup files (I do not use output of kram).
In the figures:
  - solid (noisy) line is output from case.jointup
  - the symbols are smeared spectra
  - black '+' are the experimental spectra
  - blue 'o' and red 'x' are spectra calculated by w2k version 17
  - green '+' and yellow '*' are spectra calculated by w2k version 16
  - y-axis denotes permittivity*E (in eV).

That is why I have concluded that joint function in w2k version 17 has a bug in calculation of the optical permittivity. But I have not tested non-magnetic cases, I did it only for bcc Fe (sp+so).

Hoping it helps.
If I can help more, please let me know..

With my regards

Jaro



On 04/10/17 16:40, Gavin Abo wrote:

Dear Jaro,

I thought the spin-polarized SO optic normalization was broken in older versions of WIEN2k and was fixed in 17.1:

https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16011.html

Is it still broken?

Kind Regards,

Gavin

On 10/3/2017 4:30 PM, Jaroslav Hamrle wrote:
Hallo,

to calculate optical properties of Ni, after calculating electronic structure being spin-polarized and being with spin-orbit, do:

1) create both case.inop (your file looks correct) and case.injoint

Example of case.injoint is:
==== example of case.injoint =======
    1  9999 9999              : LOWER,UPPER and (optional) UPPER-VAL BANDINDEX
   0.0000    0.00100   1.0000 : EMIN DE EMAX FOR ENERGYGRID IN ryd
eV                            : output units  eV / ryd  / cm-1
     4                        : SWITCH
     9                        : NUMBER OF COLUMNS
   0.1  0.1  0.3              : BROADENING (FOR DRUDE MODEL - switch 6,7 -
ONLY)

SWITCH:

   0...JOINTDOS FOR EACH BAND COMBINATION
   1...JOINTDOS AS SUM OVER ALL BAND COMBINATIONS
   2...DOS FOR EACH BAND
   3...DOS AS SUM OVER ALL BANDS
   4...Im(EPSILON)
   5...Im(EPSILON) for each band combination
   6...INTRABAND contributions
   7...INTRABAND contributions including band analysis
===== end example case.injoint ====

Now, you have to decide if you want to calculate optics at finer k-mesh than electronic structure, or the same mesh. In case electronic structure is calculated with k-mesh 30x30x30, it is good enough for Imxy and MOKE.

2a) when keeping the same k-mesh for optical calculations as for electronic structure, do:

  x lapw2 -p -fermi -up -so
  x optic -p -up -so   (your command in your email is opticc,  i.e. complex variant of command optic; opticc should be used when the structure lacks point symmetry, which Ni does not)
  x joint -up
  x kram -up

2b) when you want mesh for optical calculations to be finer, do:
  x kgen -so (to generate finer mesh)
  in third line in case.in2, change value of TETRA to be 101
  x lapw1 -p -up
  x lapw1 -p -dn
  x lapwso -up -p
  x lapw2 -p -fermi -up -so
  x optic -so -up -p
  x joint -up -p
  x kram -up


3) When using w2k version 17.1, there is a bug in the function joint when electronic structure is spin-polarized case with so. In this case, all optical constant outgoing function joint have half values for w2k ver 17.1 compared to previous w2k versions. So either use w2k version 16.1 or smaller, or with w2k version 17.1, simply multiply all optical constants by factor 2.

Hoping it helps
Best regards

Jaro



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