Electronic structure of MnAl3+- and MnAl2+-doped YAlO3: Prediction from the first principles

The atomic structure and electronic properties of Mn3+ and Mn2+ ions substituted for the host Al at YAlO3 have been studied from the first principles. The 2×2×2 supercell adopted for the bulk crystal phase of Pbnm symmetry allows us to simulate substitutional point defect with concentration of about 3%. To perform ab initio modeling of Mn-doped YAlO3 we were using approach of hybrid exchange-correlation functional HSE within density functional theory. We predict a decrease of the MnO bond covalency in the doped crystal with respect to the AlO bond of ideal orthorhombic YAlO3. Relatively large displacement of Y and Al atoms nearest to the F0 -center inserted to stabilize the Mn2+ ion of Mn:YAlO3 (0.17 Å towards the defect) influences the YAlO3 electronic structure. This leads to the presence of energy levels in the band gap of Mn-doped YAlO3. The F-center attracts ∼0.54 e, while the rest electron density from the missing O2− is localized mostly on the closest Mn2+ dopant.