[Pw_forum] anti-ferromagnetic calculations

[mohnish pandey]

Dear Padmaja!
                            As I am using the latest version of QE(i.e 4.2)
the 'nelup' and "neldw" variables are no longer there anymore. For magnetic
calculations starting with some initial magnetization i.e.
starting_magnetization(i). In my experience with AF calculations you should
have even number of atoms in the unitcell( unless the system is frustrated
or something like that). I did the calculation for NiO which have rocksalt
structure so there will be 2 atoms in the unit cell with ibrav = 2. But with
this I was not able to hit the ground state because there was only one Ni.
So the number mag/unitcell was not zero. But when I did the calculation with
ibrav = 1 and 8 atoms the total magnetization~0 and I am able to reach the
ground state. And as also Shrubha pointed out that you must do Lowdin
analysis to see the magnetization and check the up and down spins.
I hope it helps.

On Thu, Jan 13, 2011 at 11:25 AM, Padmaja Patnaik <
padmaja_patnaik at yahoo.co.uk> wrote:

> Dear All
>
> For an anti-ferromagnetic calculation to run in QE which of the following
> way is more correct.
> 1. specify different values of starting magnetization for different atoms
> in the compound. I mean one positive and one negative value.
>
> 2. specifying the nelup and neldown.
>
> Thanks and regards
> Padmaja Patnaik
> Research Scholar
> Dept of Physics
> IIT Bombay
> Mumbai, India
>
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>


-- 
Regards,
MOHNISH,
-----------------------------------------------------------------
Mohnish Pandey
Y6927262,5th Year dual degree student,
Department of Chemical Engineering,
IIT KANPUR, UP, INDIA
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