Abstract
We have studied the properties of SnO6 octahedra-containing perovskites and their derived structures using ab initio calculations with different density functionals. In order to predict the correct band gap of the materials, we have used B3LYP hybrid density functional, and the results of B3LYP were compared with those obtained using the local density approximation and generalized gradient approximation data. The calculations have been conducted for the orthorhombic ground state of the SnO6 containing perovskites. We also have expended the hybrid density functional calculation to the ASnO3/A׳SnO3 system with different cation orderings. We propose an empirical relationship between the tolerance factor and the band gap of SnO6 containing oxide materials based on first principles calculation.
(a) Structure of ASnO3 for orthorhombic ground state. The green ball is A (Ba, Sr, Ca) cation and the small (red) ball on edge is oxygen. SnO6 octahedrons are plotted as polyhedron. (b) Band gap of ASnO3 as a function of the tolerance factor for different density functionals. The experimental values of the band gap are marked as green pentagons. (c) ASnO3/A׳SnO3 superlattices with two types cation arrangement: [001] layered structure and [111] rocksalt structure, respectively. (d) B3LYP hybrid functional band gaps of ASnO3, [001] ordered superlattices, and [111] ordered superlattices of ASnO3/A׳SnO3 as a function of the effective tolerance factor. Note the empirical linear relationship between the band gap and effective tolerance factor. [Display omitted]
•We report the hybrid functional band gap calculation of ASnO3 and ASnO3/A׳SnO3.•The band gap of ASnO3 using B3LYP functional reproduces the experimental value.•We propose the linear relationship between the tolerance factor and the band gap.