A comparative study on the high and low symmetric structures of (LaMnO3)n/(LaNiO3)n superlattices by first-principles calculations

Abstract

We have employed the + U extension of Generalized Gradient Approximation (GGA) of the Density Functional Theory (DFT) to study the (LaMnO3)n/(LaNiO3)n oriented (0 0 1) superlattices. We built superlattices for both high (cubic) and low (rhombohedral) symmetry structures. Structural, electronic, and interfacial energy calculations reveal charge transfer from Mn to Ni interfacial atoms in both structures inducing magnetic moment at the Ni atom. Magnetic calculations show that the Mn and Ni atoms are ferromagnetically coupled. Our results indicate that the amount of charge transfer and magnetic moment are largest in the (LaMnO3)1/(LaNiO3)1 than (LaMnO3)2/(LaNiO3)2, and in the low symmetry (rhombohedral) than the high symmetry (cubic) superlattices, because of the Transition Metal-Oxygen (TMO) bonds created, and suggest the low symmetric structure for more efficient magnetic moment in the (LaMnO3)/(LaNiO3) superlattices.