The electronic structure of novel high-pressure and high-temperature phases of Mn2O3: exploring perovskite and ilmenite-type structures

Abstract

Novel manganese phases termed perovskite ζ-Mn₂O₃ and ilmenite ε-Mn₂O₃ have been synthesized under high-pressure and high-temperature conditions. We employ X-ray absorption and X-ray emission spectroscopy techniques to explore the electronic structure of these compounds. Both novel phases exhibit mixed-valence character and our analysis of the Mn L_2,3 edge spectroscopy allows to determine the concentration of the different atomic sites. Particularly, we determine the average valence of both compounds and find it in good agreement with archetypical α-Mn₂O₃. Moreover, experimental resonant inelastic X-ray scattering together with multiplet theory utilizing an Anderson Impurity model Hamiltonian is used to study the crystal field and charge transfer processes in the vicinity of the Mn²⁺ crystal sites. Our analysis allows to determine the ligand field splitting, the charge transfer energy, the width of the oxygen ligand band as well as the hybridization strength, all governing the electronic transport properties of the material.