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

Novel manganese phases termed perovskite zeta-Mn2O3 and ilmenite epsilon-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,L-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 alpha-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.