Linking Interfacial Step Structure and Chemistry with Locally Enhanced Radiation-Induced Amorphization at Oxide Heterointerfaces

Nanostructured materials and their interfaces have attracted recent interest for their functionality in a wide variety of different applications. However, the origins of these properties in several instances remain unknown. One promising aspect of nanomaterials is their role in materials design for mitigating radiation damage. In particular, engineered radiation tolerant materials would exploit the presence of internal interfaces to act as recombination centers and suppress damage accumulation. Realizing this promise, however, requires a fundamental understanding of how radiation-induced defects interact with interfaces. Thus, studying the interfacial atomic structure and chemistry before and after irradiation is critical. In this study, we have performed transmission electron microscopy on a series of pristine and ion-irradiated oxide interfaces to probe radiation-induced effects. The CeO2/SrTiO3 interface, chosen as a model system for these studies, is characterized by differences in SrTiO3 terminations or steps. Our salient result is that steps are centers for preferential amorphization in SrTiO3, which we attribute to defect flow across the interface induced by non-stoichiometry in CeO2. The study concludes the interfacial atomic ordering in the form of steps thereby modifies the response to ion irradiation and suggests interface patterning as another parameter to functionalize radiation tolerant materials.