The effect of structural ordering on the magnetic, electronic, and optical properties of the LaPbMnSbO6 double perovskite

The interplay between the magnetic, electronic, and optical properties and the cation structural ordering in the LaPbMnSbO6 double perovskite is studied using the Vienna Ab Initio Simulation Package (VASP). The layer and rock-salt cation ordering types are investigated. Both of them are of great importance. The rock-salt ordering of B-site cations is one of the most frequently met cation ordering types in double perovskites; the layer ordering of both cations, which can be considered as a heterostructure, is interesting for fundamental research and experimental synthesis. It was established that the properties of the two investigated structures are strongly different. The compound with the layered structure exhibits the behavior typical of a semimetal with the ferromagnetic configuration of magnetic moments, which is unusual for a double perovskite. The rock-salt structure behaves as an antiferromagnetic insulator. Another surprising feature of the structure with the layer ordering is the coexistence of a polar phase and the metal-type conductivity. The calculated optical characteristics of the two ordered structures are compared with the experimental dates.