Atomic and Electronic Structures of the Interfaces between Perovskite La0.75Sr0.25MnO3 and Brownmillerite SrCoO2.5

Epitaxial thin films composed of perovskite and brownmillerite oxides have received increasing attention because of the novel phenomena found in these systems. Herein, the atomic and electronic structures of the La 0.75 Sr 0.25 MnO 3 /SrCoO 2.5 interface have been studied using first‐principles calculations. From the perspective of polarity compensation, three types of possible interface models are constructed, which have different interface terminations or orientation relationship. In the model where the [100] direction of SrCoO 2.5 is parallel to the interface, the interface is polar. The way to compensate polarity is atomic reconstruction. For the model with the [100] direction of SrCoO 2.5 perpendicular to the interface, there are two possible interface terminations. One is nonpolar. The other is polar, but its polarity can be compensated by electronic redistribution, i.e., the valence change of Mn from +3 to +4 at the interface, as consistently revealed by the change of the bond valence sums and magnetic moments of Mn ions. For this model with electronic redistribution, accompanied by the valence change, the MnO 6 octahedra near the interface have the largest distortion compared with the other two models. The density of states around Fermi level and the magnetic coupling across the interface are also discussed.