Probing LaMO3 Metal and Oxygen Partial Density of States Using X-ray Emission, Absorption, and Photoelectron Spectroscopy

We examined the electronic structure in LaMO3 perovskite oxides (M = Cr, Mn, Fe, Co, Ni) by combining information from X-ray emission, absorption, and photoelectron spectroscopy. Through first-principles density functional theory simulations, we identified complementary hybridization features present in the transition metal and oxygen X-ray emission spectra. We then developed a method for the self-consistent alignment of the emission data onto a common energy scale using these features, providing a valuable supplementary technique to photoelectron spectroscopy for studying the partial density of states in perovskites. The combined information from X-ray emission and absorption was used to explore trends in electronic structure characteristics under the Zaanen-Sawatzky-Allen frameworknamely the extent of metal-oxygen hybridization, band gap, and charge-transfer gap. We further established a method that allows for the experimental determination of the occupied and unoccupied band positions relative to the oxide Fermi level, as well as on an absolute energy scale.