  The electronic structure, magnetic and structural properties of the
superconductor ThFeAsN are discussed in relation to the Fe-pnictide and
Fe-chalcogenide superconductors based on results of first principles
calculations. The electronic structure is that of a high density of states
semimetal. It shows approximately nested hole and electron Fermi surfaces of Fe
$d$ character involving the $xz,yz$ and $xy$ orbitals. There is a strong
tendency towards magnetism at the GGA level, and this magnetism is important
for describing the Fe-As bonding, but greatly overestimates the magnetic
ordering. The lowest energy magnetic state at the GGA level is the stripe
order, and this particular order couples strongly to electrons near $E_F$.
ThFeAsN is therefore strongly similar to the Fe-pnictide family of
superconductors, although it is a particularly anisotropic member.
