Structural and electronic structures of alkaline-earth transition metal oxynitride perovskites
Résumé
Metal oxynitrides with perovskite AMO3-xNx structure have been shown to exhibit promising optical, dielectric, magnetoresistive or photocatalytic properties. They are formally obtained from perovskite oxides via substitution of oxygen by nitrogen. However, due to the stability of the M-O bond, only a limited number of nitrogen-doped perovskites AMO3-xNx and stoichiometric oxynitrides (AMO2N and AMON2) has been synthesized and studied so far. Different case studies revealed that the oxidation states of the cations, the O/N ratio, as well as the anion ordering can significantly affect their properties. With the aid of density functional theory calculations, the effect of O/N anion ordering was investigated for a series of different metallic perovskite phases AMO2N (A = Rb, Sr, Yand M = Cr, Mo, W). Results indicate that well-defined cis-MO4N2 octahedra in the structures are energetically preferred over trans-MO4N2 octahedra, leading to zigzag MN chains in the materials. ©2016 The Ceramic Society of Japan. All rights reserved.