  The electronic structure of the antiferromagnet uranium nitride (UN) has been
studied by angle resolved photoelectron spectroscopy using soft X-rays
(hn=420-520 eV). Strongly dispersive bands with large contributions from the U
5f states were observed in ARPES spectra, and form Fermi surfaces. The band
structure as well as the Fermi surfaces in the paramagnetic phase are well
explained by the band-structure calculation treating all the U 5f electrons as
being itinerant, suggesting that itinerant description of the U 5f states is
appropriate for this compound. On the other hand, changes in the spectral
function due to the antiferromagnetic transition were very small. The shapes of
the Fermi surfaces in a paramagnetic phase are highly three-dimensional, and
the nesting of Fermi surfaces is unlikely as the origin of the magnetic
ordering.
