Local and global properties of the ordered double perovskite Sr2YTaO6: an ab initio study

A density functional-based method has been used to investigate the systematic trends for the structural parameters and electronic structure of four phases of the ordered double-perovskite Sr2YTaO6 compound. The chemical bonding has been investigated by making use of topological analyses grounded on the theory of atoms in molecules (AIM). Local charge and local charge transfer results lead to a prediction of strong ionic behavior. Using a quasiharmonic Debye model, in which the phononic effects are taken into account, studies of the effects of temperature on the heat capacity and entropy are performed. We have found that octahedral coordination of each of the structures has a negligible impact on the electronic and bonding properties. However, distortions from cubic structure lead to increases in the band gap. Optical as well as thermal and transport properties are also analyzed.