[Wien] FeO LDA+U

[Ashley Alford]

Dear Dr. Blaha,

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


FeO AFM U SIC
R   LATTICE,NONEQUIV.ATOMS:  3
MODE OF CALC=RELA unit=bohr
   5.788586  5.788586 28.358164 90.000000 90.000000120.000000
ATOM  -1: X=0.00000000 Y=0.00000000 Z=0.00000000
           MULT= 1          ISPLIT= 4
Fe1        NPT=  781  R0=0.00005000 RMT=    2.0000   Z: 26.0
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                      0.0000000 1.0000000 0.0000000
                      0.0000000 0.0000000 1.0000000
ATOM  -2: X=0.50000000 Y=0.50000000 Z=0.50000000
           MULT= 1          ISPLIT= 4
Fe2        NPT=  781  R0=0.00005000 RMT=    2.0000   Z: 26.0
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                      0.0000000 1.0000000 0.0000000
                      0.0000000 0.0000000 1.0000000
ATOM  -3: X=0.25000000 Y=0.25000000 Z=0.25000000
           MULT= 2          ISPLIT= 4
       -3: X=0.75000000 Y=0.75000000 Z=0.75000000
O          NPT=  781  R0=0.00010000 RMT=    1.8000   Z:  8.0
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                      0.0000000 1.0000000 0.0000000
                      0.0000000 0.0000000 1.0000000
   12      NUMBER OF SYMMETRY OPERATIONS
-1 0 0 0.0000000
  0-1 0 0.0000000
  0 0-1 0.0000000
        1
-1 0 0 0.0000000
  0 0-1 0.0000000
  0-1 0 0.0000000
        2
  0-1 0 0.0000000
-1 0 0 0.0000000
  0 0-1 0.0000000
        3
  0 0-1 0.0000000
-1 0 0 0.0000000
  0-1 0 0.0000000
        4
  0-1 0 0.0000000
  0 0-1 0.0000000
-1 0 0 0.0000000
        5
  0 0-1 0.0000000
  0-1 0 0.0000000
-1 0 0 0.0000000
        6
  0 0 1 0.0000000
  0 1 0 0.0000000
  1 0 0 0.0000000
        7
  0 1 0 0.0000000
  0 0 1 0.0000000
  1 0 0 0.0000000
        8
  0 0 1 0.0000000
  1 0 0 0.0000000
  0 1 0 0.0000000
        9
  0 1 0 0.0000000
  1 0 0 0.0000000
  0 0 1 0.0000000
       10
  1 0 0 0.0000000
  0 0 1 0.0000000
  0 1 0 0.0000000
       11
  1 0 0 0.0000000
  0 1 0 0.0000000
  0 0 1 0.0000000
       12

----------------------------------------------------


Fe 1
Ar 3 5
3, 2,2.0  N
3, 2,2.0  N
3,-3,2.5  N
3,-3,0.0  N
4,-1,1.0  N
4,-1,0.5  N
Fe 2
Ar 3 5
3, 2,2.0  N
3, 2,2.0  N
3,-3,0.0  N
3,-3,2.5  N
4,-1,0.5  N
4,-1,1.0  N
O
He 3 5
2,-1,1.0  N
2,-1,1.0  N
2, 1,1.0  N
2, 1,1.0  N
2,-2,1.0  N
2,-2,1.0  N
****     End of Input
****     End of Input

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> _______________________________________________
>> Wien mailing list
>> 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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