TCM
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Check2xsf and Spin in FeO

An example of visualising antiferromagnetic spin in FeO, continuing from the previous page on crystals.

FeO.cell
%BLOCK LATTICE_CART
 0.000 4.332 4.332
 2.166 0.000 2.166
 2.166 2.166 0.000
%ENDBLOCK LATTICE_CART

%BLOCK POSITIONS_FRAC
  O   0.25 0.50 0.50
  O   0.75 0.50 0.50
 Fe   0.00 0.00 0.00   SPIN 2
 Fe   0.50 0.00 0.00   SPIN -2
%ENDBLOCK POSITIONS_FRAC

kpoints_mp_grid 1 3 3
kpoints_mp_offset 0.25 0 0
FeO.param
cut_off_energy  = 45 ry
iprint          = 1
opt_strategy : speed
spin_polarized : true

(This calculation will take longer to run than the previous examples, but still under a minute on a single core of a Haswell.)

To see the spin density in a single cell, simply run:

$ check2xsf -s FeO.check FeO.spin.xsf

The spin density is sharply concentrated close to the iron atoms, which are displayed as largish spheres, so one must set the isosurface value at a surprisingly small fraction of the peak values in the dataset. Here the isovalue is 0.06, and the peak is 8.6. Two unit cells are shown, with the repetition being in the y direction. As oxygen and iron are both shown as red, Display, Atomic Symbols has been turned on.

FeO and spin density

The alternating spins in the layers of Fe are clearly seen.