Structural, electronic properties and enhancement of electrical polarization in Er₂NiMnO₆/La₂NiMnO₆ superlattice by first-principles calculations

Employing first-principles calculations, structural, electronic properties of new multiferroic material Er₂NiMnO₆/La₂NiMnO₆ perovskite superlattice are investigated. This structure is computed as monoclinic phase with obvious distortion. The average in-plane anti-phase rotation angle, average out-of-plane in-phase rotation angle and other microscopic features are reported in this paper. Ni and Mn are found in this superlattice that stay high spin states. These microscopic properties play important roles in multiferroic properties. Based on these microscopic features, the relationship between the direction of spontaneous polarization and the order of substitution in neighboring A-O layers is explained. Finally, we try to enhance the electrical polarization magnitude by 32% by altering the previous superlattice as LaEr₂NiMnO₇ structure. Our results show that both repulsion force of A site rare earth ions and the arrangement of B site ions can exert influences on spontaneous polarization.