[Wien] accuracy of magnetic moment

[tran at theochem.tuwien.ac.at]

In this case it's clear that if the environment is not
the same for all Fe (two up neighbors or one up and one down neighbors),
then different moments are obtained.


On Saturday 2016-05-07 12:16, Yundi Quan wrote:

>Date: Sat, 7 May 2016 12:16:44
>From: Yundi Quan <quanyundi at gmail.com>
>Reply-To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
>To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
>Subject: Re: [Wien] accuracy of magnetic moment
>
>I started with AFM magnetic structure by configuring case.inst using instgen -ask. Fe has the same Muffin-tin sphere and local environment. Initially, spin up Fe has a moment of 2.5,
>while the spin down Fe has a moment of -2.5. The Fe Muffin-tin radius is 2.31. RKMax=7  And I used P1 symmetry. There is no warning messages during the scf run. I increased the k-mesh
>gradually and did not find any change in moments. The total energy does not change with k-mesh. There are four distinct types of moments, 1.98, 2.06 and -1.98 and -2.06. Could it be
>because of spin density wave? The magnetic configuration that I calculated involve the following magnetic configuration up up up up dn dn dn dn in a one dimensional chain. Could it be
> that the middle two Fe have larger moment because their nearest neighbors are all pointing in the same direction?
>
>
>On Sat, May 7, 2016 at 4:09 PM, <tran at theochem.tuwien.ac.at> wrote:
>      Did you start the SCF iterations with an electron density
>      having the AFM structure? If not, do it by generating AFM density
>      (lstart and dstart) having exact opposite magnetic moments
>      (with proper case.inst).
>
>      If you do not start calculation with AFM density, then
>      you may end up in another magnetic structure, or you
>      would need to run more SCF iterations to reach the AFM
>      structure.
>
>      F. Tran
>
>      On Saturday 2016-05-07 08:52, Yundi Quan wrote:
>
>            Date: Sat, 7 May 2016 08:52:37
>            From: Yundi Quan <quanyundi at gmail.com>
>            Reply-To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
>            To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
>            Subject: [Wien] accuracy of magnetic moment
>
>            Hi,I carried out AFM calculation a Fe compound. The resulting magnetic moments are -1.98 and 2.06. Is it reasonable to assume that they are equal and opposite?
>
>
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