Abstract:
Using ab initio calculations by the density functional theory in the LDA + U approximation, the features of the formation process of intrinsic defects in crystals of doped manganite with a perovskite-like structure are studied. It is shown that the nature of the energy barrier, which provides the relative stability of the material of high-quality La$_{0.8}$Sr$_{0.2}$MnO$_{3+\delta}$ films with a stoichiometric composition with respect to oxygen, due to the different energy of formation of metal and oxygen vacancies. In this case, the physical mechanism for the formation of an oxygen-excessive state of the crystal realizes in accordance with a well-known physical model, by forming additional cation-deficient crystal cells by means of the depletion of complete ones.
Keywords:doped manganite, ab initio calculations, defect formation mechanism, oxygen and cation vacancies, formation energy of point defects.