Electronic Structure And Magnetic Properties Of EuTiO₃Based On He First-Principle Calculations

Perovskite structures have been extensively studied in recent years. Our calculationsare performed using the first-principle density-functional theory. The generalized-gradientapproximation （GGA）+U methods are used to elaborate the electronic structure andmagnetic properties of bulk EuTiO₃and EuTiO₃（001） Surfaces. We considerferromagnetic （F）, and antiferromagnetic A-, C-, and G-type arrangements in the studys ofbulk EuTiO₃, we find that the G-type antiferromagnetic structure is the most stable whenU≤4eV, to the contrary, when U≥5eV, the ground state is ferromagnetic. The magneticallyordered structures and band gap are varied with U. We also studied the properties ofEuTiO₃-δ.The total energy studies show that the ground state ofEuTiO₃-δis ferromagnetic.We find thatEuTiO₃-δis metal from the total density of states （DOS）.The oxygen-deficientEuTiO₃（001） surface calculated results show that the spin-flip ferromagnetic structurebecomes stable with and without the oxygen vacancies for EuO-termination surface.Besides, for TiO2-termination surface, it is interesting to see that the G-typeantiferromagnetic state is stable without the oxygen vacancies, but the ferromagnetic statebecomes stable while the oxygen vacancies appear, which is independent of theconcentrations of oxygen vacancies.