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setting the total magnetic moment

Posted: Wed Jun 09, 2010 3:14 pm
by Danny
Dear Vasp users/admin

Is it possible in VASP to set the total magnetic moment of the unitcell(of a bulk material)?
I know MAGMOM can be used to set spins for all atoms, however all I know is the total magnetic moment caused by the substitution of 1 atom...In which case I guess part of the total magnetic moment will be due to this substituted atom and part due to its neighbors.

So does there exist an input parameter to do this, or should I just set the magnetic moment of the substituted atom equal to the total magnetic moment and hope VASP can translate this into the correct total magnetic moment?

thx
Danny

setting the total magnetic moment

Posted: Wed Jun 09, 2010 8:03 pm
by alex
Have you thought about combining NUPDOWN and MAGMOM? Or did I get you wrong?

Cheers,

alex

setting the total magnetic moment

Posted: Wed Jun 09, 2010 8:03 pm
by alex
Hi Danny,

have you thought about combining NUPDOWN and MAGMOM? Or did I get you wrong?

Cheers,

alex

setting the total magnetic moment

Posted: Thu Jun 10, 2010 10:35 am
by Danny
Thanks for the advice Alex. It might do the trick, although it might limit the freedom of the system a bit to much.

The problem with NUPDOWN is that it fixes your magnetic moment, but I do not know how much it is exactly. What I would like to do is tell VASP the total magnetic moment is (for example) 4, and allow VASP to relax to the nearby local magnetic minimum, which could be 3 or 5 or 4 or 3.45.

Yes I know I could just scan for the optimum magnetic configuration, the problem is that I am actually not interested in finding the magnetic moment per se (strange I know), I am looking at other properties and just would like all calculations to have a consistent magnetic moment (without having to do a detailed study of each system to find it's optimal magnetic moment, it's a bit lazy I know).

any other options?(beside ignoring magnetism altogheter :-) )

cheers,
Danny

setting the total magnetic moment

Posted: Thu Jun 10, 2010 1:15 pm
by alex
I think you have to go through this misery.

Cheers,

alex