An ab initio characterization of the electronic structure of LaCo $_{x}$ Fe $_{1- x}$ O $_{3}$ for x  ≤ 0.5 (Phys. Status Solidi B 9/2016)

摘要

Simple perovskite-type materials have the general chemical formula ABO3. While that already offers a broad variability in choosing A and B, additional tuning of the properties can be achieved by partial substitution of the A and/or B site. As such, this class of materials has found widespread use in chemical and electrochemical applications, e.g. in catalytic conversions, electrolysers and fuel cells. Calculating the changes in lattice parameters and electronic structure (oxidation and spin states, density of states) caused by the A and/or B site substitutions, deepens the understanding and enables prediction of the associated experimental trends, thereby increasing the potential applicability of these perovskite-type materials. Geatches et al. (pp. 1673–1687) have focused on the elaboration of the electronic structure of LaCoxFe1-xO3 with varying ratios of Fe/Co, revealing that increasing the ratio of Co to Fe changes their rather semiconducting nature toward insulating. This behaviour can be related to the decrease in the number of (conducting) O–Fe–O bonds and the increase in (insulating) O–Co–O bonds.