# Example: Spin polarization: antiferromagnetic iron¶

Download BetaIron.run

With the UNRESTRICTED keyword we do a spin polarized calculation. Normally this would converge to the ferromagnetic solution.

With the SpinFlip keyword we make sure that we start with an antiferromagnetic density.

For antiferromagnetic iron we need a larger unit cell of two atoms. Since these atoms appear to the program as symmetry equivalent we have to specify them as separate types.

\$ADFBIN/band << eor

TITLE Beta iron

UNITS
length Angstrom
END

! The two iron atoms have different "types" to break the symmetry
ATOMS
Fe.a   0.0    0.0    0.0
Fe.b  -1.435 -1.435  1.435
end

Lattice
-1.435  1.435  1.435
1.435 -1.435  1.435
2.87   2.87  -2.87
End

CONVERGENCE
CRITERION 1.0e-4
Degenerate default
SpinFlip 2  ! Flip (startup) spin density at second atom
END

BasisDefaults
BasisType DZ
Core Large
End

UNRESTRICTED

end input
eor