[Wien] FeO LDA+U

[Peter Blaha]

Yes, we have done such calculations.

As I mentioned in my last email, eventually change the occupation of
the densitymatrix.

More specifically, edit     case.dmatdn

Change all larger numbers to small values (like 0.1e-01 at most)

Change the first number in line 10  (this is the occupation of the
d-z2 orbital) to 0.9

runsp -orb   should do the rest.

> Thanks for addressing this question re: getting a gap
> in FeO. I am using an AF rhombohedral cell which has
> two Fe atoms and two O atoms. This is just like the CoO
> struct file from the example files provided with Wien2k.
> 
> The struct file and inst file are below.
> 
> If you know of anyone who has done this calculation
> successfully, please let me know.
> 
> Thanks very much,
> Ashley
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> On Wed, 28 Jun 2006, Peter Blaha wrote:
> 
> > Do you have an AF rhombohedral cell with 2 Fe atoms and one Ni ?
> >
> > The Fe have opposite spin ?
> >
> > If I remember correctly, there was no problem in going from GGA to LDA+U
> > and getting an insulator.
> >
> > However, you can play with the density matrix
> > and occupy the d-z2 (m=0) orbital. Use  x org -up/dn and runsp -orbc for
> > some steps, until you release it using runsp -orb
> >
> >
> >> I am trying to do an LDA+U calculation for FeO in the antiferromagnetic
> >> configuration (AFM).
> >> I find that even when I start the calculation with the antiferromagnetic spin
> >> configuration and a large
> >> value of U (up to 9eV, J = 0.89), the system goes back to a metallic
> >> ferromagnetic state.
> >> I have tried modifying the density matrices and restarting.In this case, either
> >> the same happens or the
> >> Fe magnetic moments wander around and never converge.
> >>
> >> Has anyone converged a gapped AFM state for FeO?
> >> Or at least has anyone noticed the above problem?
> >>
> >> In the literature it is a mentioned a few times  that one needs to fully occupy
> >> the A1g orbital (rhombohedral system) and deplete the Eg orbitals in order
> >> to open a gap.
> >> Has anyone done this successfully for FeO?
> >>
> >> Was it sufficient to start with a particular configuration or was modification
> >> of the density matrices necessary?
> >>
> >> Any help you can provide is greatly appreciated.
> >>
> >> Ashley
> >>
> >> PS. I am running WIEN2k_04.11 (Release 1/11/2004)
> >>
> >>
> >>
> >>
> >>
> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> John Ashley Alford II
> >> Oak Ridge National Laboratory
> >> PO Box 2008  MS6164
> >> Oak Ridge, TN  37831-6164
> >> Phone: (865) 576 - 6269
> >> FAX:   (865) 241 - 0381
> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> _______________________________________________
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> >> Wien at zeus.theochem.tuwien.ac.at
> >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> >>
> >
> >
> >                                      P.Blaha
> > --------------------------------------------------------------------------
> > Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> > Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
> > Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
> > --------------------------------------------------------------------------
> > _______________________________________________
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> >
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> 


                                      P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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