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Ferromagnetic and Antiferromagnetic calculations

Posted: Tue Feb 17, 2009 3:19 pm
by goja25
Hi everyone!
I am trying to do FM & AFM calculations in doped DMS system. I want to specify initial magnetic moment to the impurity only - Mn atoms. I have a 38 atom supercell of In17Mn2As19. I want to assign magnetic moment to only Mn.
How to do it?????
For FM:
Magmom = 17*0 19*0 1 1
For AFM:
Magmom = 17*0 19*0 1 -1 - is it correctly?

My POTCAR file ofcorse contain the Mn pseudopotential twice.
Please help
Margo

Ferromagnetic and Antiferromagnetic calculations

Posted: Wed Feb 18, 2009 6:30 am
by forsdan
I don't see why you need the Mn pseudopotential twice. You can still specify the initial magnetic moments to the two Mn atoms by using

MAGMOM = 17*0 19*0 1 1
or
MAGMOM = 17*0 19*0 1 -1

in the two respective cases so the Mn pesudopotentials doesn't have to appear twice in the POTCAR-file. However, do you know if the two different magnetizations are stable? It might otherwise happen that the two calculations converge to the same results. If you know that there are two stable solutions and you know the magnetization values it can sometimes be good to multiple the known magnetic moments on the atoms by a factor of 1.2-1.5 and use that as the initial magnetic moment, This can improve the convergence to magnetic state in question.

Cheers
/Dan

<span class='smallblacktext'>[ Edited Wed Feb 18 2009, 07:32AM ]</span>