[Wien] orbital moment

[Stefaan Cottenier]

>We could extract the orbital moment for our case and after calculating the
>( orbital moment / spin moment ) ratio we found that it is almost half
>of the corresponding experimental value. Would you (or others) kindly
>tell me is there any factor of 2 hidden in the orbital moment.
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For transition metals, it is rather common that LDA/GGA severely 
underestimate the orbital moment. For instance, for bcc Fe LDA finds 
about 0.04 mu_B instead of the experimental 0.08 mu_B. There is no 
general recipe yet how to improve on that. An ad hoc solution is the 
orbital polarization method (see one of the 3 options of the ORB 
package), but this is merely 'fitting' the orbital moment. Another 
solution is described in P. Novak, PRB 67 (2003) 140403. Depending on 
your system, LDA+U could help as well.

Stefaan

>>>I am trying to calculate the orbital moments of atoms in a Magnetic system.
>>>I have added the spin orbit correction as well as density matrix
>>>calculation (with rindex=1 and lsindex=3) to my scf but in the results
>>>(output and scf files) I can not find the ORBxxx parameter.
>>>I would appreciate if you please tell me what is the problem?
>>>      
>>>
>>:ORBxxx is only there if LDA+U is used. For LDA+spin-orbit, run once
>>'x lapwdm -c -so -up' after your scf cycle is converged (using '1 3'
>>in case.indmc, as you seem to have done), and look in case.scfdmup for
>>the orbital moment.
>>
>>Stefaan
>>
>>
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