  X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy and
density functional theory calculations were used to study the electronic
structure of three lanthanide scandates: GdScO3, TbScO3, and DyScO3. X-ray
photoelectron spectra simulated from first principles calculations using a
combination of on-site hybrid and GGA+U methods were found to be in good
agreement with experimental x-ray photoelectron spectra. The hybrid method was
used to model the ground state electronic structure and the GGA+U method
accounted for the shift of valence state energies due to photoelectron emission
via a Slater-Janak transition state approach. From these results, the
lanthanide scandate valence bands were determined to be composed of Ln4f, O2p,
and Sc3d states, in agreement with previous work. However, contrary to previous
work the minority Ln4f states were found to be located closer to, and in some
cases at, the valence band maximum. This suggests that minority Ln4f electrons
may play a larger role in lanthanide scandate properties than previously
thought.
