Dear Farah,

I stumbled upon that work and an older question of yours in the forum similar 
to mine for that very FG system.

Even if our systems are different, did you notice whether having the right 
magnetisation had a large effect on the final energies/electronic structure? 
I'm not concerned with magnetic properties, only energies and structures; I was 
just puzzled by the fact I was getting unphysical results and inconsistent 
between similar systems (e.g., if I use a Si dopant instead of B, everything is 
fine). As you suggest, I guess it's just simple DFT trying to do its best in a 
strongly correlated system.

Kind regards,
Carlos
________________________________
De: users <[email protected]> en nombre de FARAH MARSUSI 
<[email protected]>
Enviado: martes, 16 de julio de 2019 15:43
Para: Quantum ESPRESSO users Forum
Asunto: Re: [QE-users] Odd number of electrons yields even total magnetization

​Dear Carlos,

If everything in your input file is OK, when DFT suffers so much from self 
interaction error, e.g. for a highly correlated system, this may happen. Please 
see : " Carbon 144, 615 (2019).

Best wishes,

Farah.

On Tue, 07/16/2019 09:34 AM, "Ayestaran Latorre, Carlos" 
<[email protected]> wrote:
Hi,

I have a system consistent of a diamond slab with a boron substitutional 
defect, an adsorbed hydroxyl and an adsorbed hydrogen on the surface. The 
system has an odd number of electrons (487) and I run a spin polarized 
(nspin=2) structural relaxation (see attached). One would expect an odd value 
for the total magnetization, but the it quickly converges to zero.

I assumed this would be a side effect of smearing allowing partial electronic 
occupations (I employed gaussian smearing with degauss=0.02). I tried lowering 
the smearing value down to 0.001, both for gaussian and mv smearing, but only 
managed to get total magnetization ~ 0.3 Bohr mag/cell in both cases. Fixing 
tot_magnetization=1, however, yields a noticeably higher final energy (~0.3 eV).

When I run a structural relaxation on a similar system (with an adsorbed H2O 
molecule instead of the hydroxyl+hydrogen fragments), the total magnetization 
satisfyingly reaches 1 Bohr mag/cell rather quickly. Other combinations (for 
example, without the H2O molecule at all) also give total magnetization values 
that don't match the even/odd number of electrons.

Regards,
Carlos Ayestaran Latorre




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