[QE-users] Expectation values of total angular momentum in SOC case

[Thomas Brumme]

Dear Paolo, (or Dear all,)

could this be a problem of the specific pseudopotential?

I tested with US and PAW in the Hf system and didn't find any 
inconsistency. Yet, I even get in the monolayer WSe2 the wrong spin 
state at the conduction-band minimum. It should be - due to symmetry, at 
least what I remember from a lot of publications - either spin up or 
spin down. I get for the expectation value of Sz 0.45411. Since both Sx 
and Sy are 0 this can only mean that I have something which is a 
combination of spin up and down. Or the wave function is not properly 
normalized, but this should be detected by PW, right?

I ask for the pseudo since I remember that I had problems with 
relaxations when using the W.rel-...paw... of the pslibrary. Using a 
slightly different pseudo (which I created some time ago with Lorenzo 
when I was in Paris) the relaxations work and also the electronic 
structure and everything was fine... Could it be, that only the spin 
part is affected?

Or is it just wrong that everyone says that in WSe2 the conduction-band 
minimum at the K point is spin up? (question to the audience)

Regards

Thomas


On 1/23/20 5:10 PM, Paolo Giannozzi wrote:
> On Thu, Jan 23, 2020 at 5:00 PM Thomas Brumme 
> <thomas.brumme at uni-leipzig.de <mailto:thomas.brumme at uni-leipzig.de>> 
> wrote:
>
>     Or is there something missing in the PAW case which is not
>     important for US-PP?
>
>
> if you regularly get 1/2 for norm-conserving / ultrasoft and  less 
> than that with PAW, it is very likely that there is something missing 
> in the PAW case
>
> Paolo
> -- 
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
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-- 
Dr. rer. nat. Thomas Brumme
Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry
Leipzig University
Phillipp-Rosenthal-Strasse 31
04103 Leipzig

Tel:  +49 (0)341 97 36456

email: thomas.brumme at uni-leipzig.de

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