[Wien] mBJ + SOC :: spin-orbit splitting reduction

[Peter Blaha]

Hi,

Sorry, I have no idea what the SO splitting of those previous 
calculations has been.

In order to get an estimate, compare the partial charges of those 
splitted states. If there is a slight change in hybridization with 
slightly modified s,p,d character of the two atoms, it may explain the 
modified SO splitting.

I'm also not sure at all if the character of the bands using mBJ is 
better than in PBE, in fact I doubt it a little bit.

Eventually you could play with correlation, i.e. couple mBJ exchange 
with PBE correlation instead of LDA.

Am 05.02.2015 um 21:46 schrieb Martin Gmitra:
> Dear Wien2k developers,
>
> We are observing underestimating trend of spin-orbit coupling
> splittings of Gamma_{15} bands in zinc-blende semiconductors.
>
> For instance in GaAs, the Gamma_{15v} splits to Gamma_{8v} and
> Gamma_{7v} by the values of about 0.29 eV, while experiment gives 0.34
> eV. PBE calculations gives 0.32 eV. Similar one sees for Gamma_{15c}
> which splits due to spin-orbit to Gamma_{8c} and Gamma_{7c} where mBJ
> gives 0.156 eV and PBE 0.181 eV. This one can compare to 0.174 eV from
> GW+SOC calculations [PRL 96, 086405].
>
> In PRB 82, 205212 you present two implementations of mBJ, within
> Wien2k and VASP. Could you please provide information whether both the
> implementations provide the same spin-orbit splittings of Gamma_{15}
> states?
>
> In case they are the same, which part of the Becke-Johnson approach
> can be responsible for such a reduction?
>
> Best regards,
> Martin Gmitra
> Uni Regensburg
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-- 
Peter Blaha
Inst.Materials Chemistry
TU Vienna
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Austria
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