Hi,
Sodium metal has an odd number of electrons per primitive unit cell
(which contains a single atom), and however is nonmagnetic. The same
applies to aluminum. This is the result of having a large overlap
between orbitals, making the (in principle) spin up and spin down energy
separation much smaller than the bandwidth so that spin up and down
electrons are equaled in population. Did you verify whether this is your
case?
Regards,
José Carlos
El 16/07/2019 a las 15:34, Ayestaran Latorre, Carlos escribió:
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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