Surface science of bulk-terminated cubic perovskite oxides

Perovskite oxides possess great potential for many applications, such as (photo)catalysis, fuel cells, electronics or spintronics. The bottleneck for their practical use lies in detailed understanding of the materials surfaces at the atomic scale: There is an inherent problem with the stability of perovskites at operating conditions, and a detailed understanding of their interaction with the ambient environment is currently lacking. We have recently pioneered how to prepare well-defined surfaces of two cubic perovskites, KTaO3 and SrTiO3, suitable for surface-science studies [Science 359, 572 (2018)]. These surfaces represent a perfect starting point for applying the analytical techniques of surface science and studying the detailed interaction of these materials with molecules from the external atmosphere. Understanding these interactions is essential for optimizing catalytic reactions in applications like fuel cells or photocatalytic light harvesting. Further, the bulk-terminated surfaces used in this work provide access to bulk properties of the materials, such as special electronic states or ferroelectricity. Detailed understanding of these properties aims towards opening new routes in oxide electronics and enabling new generation of electronic devices operating beyond binary logic.