[Pw_forum] Co Pseudopotential

[heather kulik]

Izaak,

If you really are getting S=1 for the total spin in your calculation, then you have an even number of electrons in your system. Neutral cobalt has an odd number of valence electrons, 3d74s2, (hence the S=3/2) so this likely means that you have an odd number of electrons in whatever you chose for your surface. 

That's not to say you couldn't run into other problems. If you mean you see S=1 locally, e.g. from PDOS, you are likely getting charge transfer between the atom and the surface, and you may observe something that looks like S=1 on Co. I would need more information about your "all electron calculation" reference from the literature (i.e. is it Co on the same surface and with the same functional?) in order to suggest anything further.

Hope that helps,
Heather Kulik
Stanford University
On Monday, August 8, 2011 at 11:06 AM, Izaak Williamson wrote: 
> Hello everyone,
> 
> I am trying to calculate the magnetic spin of Co adsorbed onto a surface. The literature that I am comparing my values with says the Co spin is 3/2 from an all-electron calculation and I am getting S=1. The pseudopotential that I am using for Co is Co.pbe-nd-rrkjus.UPF. Is there something about this pseudopotential that is giving me an incorrect spin? Should I be using a different pseudopotential?
> 
> Thanks for any help.
> 
> -- 
> Izaak Williamson
> Research Assistant
> Physics Department
> Boise State University
> 
> 
> 
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