  We report on the electronic structure of the perovskite oxide CaCrO3 using
valence-band, core-level, and Cr 2p - 3d resonant photoemission spectroscopy
(PES). Despite its antiferromagnetic order, a clear Fermi edge characteristic
of a metal with dominant Cr 3d character is observed in the valence band
spectrum. The Cr 3d single particle density of states are spread over 2 eV,
with the photoemission spectral weight distributed in two peaks centered at ~
1.2 eV and 0.2 eV below EF, suggestive of the coherent and incoherent states
resulting from strong electron-electron correlations. Resonant PES across the
Cr 2p - 3d threshold identifies a 'two-hole' correlation satellite and yields
an on-site Coulomb energy U ~4.8 eV. The metallic DOS at EF is also reflected
through the presence of a well-screened feature at low binding energy side of
the Cr 2p core-level spectrum. X-ray absorption spectroscopy (XAS) at Cr L3,2
and O K edges exhibit small temperature dependent changes that point towards a
small change in Cr-O hybridization. The multiplet splitting in Cr 2p core level
spectrum as well as the spectral shape of the Cr XAS can be reproduced using
cluster model calculations which favour a negative value for charge transfer
energy between the Cr 3d and O 2p states. The overall results indicate that
CaCrO3 is a strongly hybridized antiferromagnetic metal, lying in the regime
intermediate to Mott-Hubbard and charge-transfer systems.
