[Wien] Interesting effect of RLO's with Spin Orbit

[Peter Blaha]

Most likely, you ran into approximate linear dependency and got 
ghostbands in the occupied regions, so that EF dropped into the valence 
bands.

It does not make sense to add RLOs for O-p

Am 21.04.2011 13:30, schrieb David Tompsett:
> Dear All,
>
> I have been performing calculations with GGA+U with spin-orbit on an Fe
> and oxygen based material. I have noticed an unusual effect when using
> RLO's ( the relativistic local orbitals) for the oxygen p-states. I
> applied the +U orbital potential only to the Fe ion and then applied
> spin-orbit coupling inside the Fe and oxide spheres.
>
> Without using RLO's for the oxygen p-orbitals the DOS shows a good band
> gap (~3eV). However, when I add RLO's for the oxygen p-states I find
> that there are states inside the band gap (significant ~0.1
> states/eV/FU). The states have the d-character of the Fe ions. It
> appears that the flexibility introduced by the RLO's on the oxygen are
> changing the description of the potential such that the groud state has
> d-orbital character inside the gap.
>
> Does anyone have experience with such an effect? I am unsure as to
> whether the effect is real. The oxygen atoms are light, so I expected
> the RLO's would have little effect.
>
> I did sensible things like converge with respect to the emax in
> case.in1, k-points, IFFT factor=4.
>
> Many thanks for your help,
> David Tompsett.
>
>
>
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-- 
Peter Blaha
Inst.Materials Chemistry
TU Vienna
Getreidemarkt 9
A-1060 Vienna
Austria
+43-1-5880115671