Structural study of nickelate based heterostructures
Heterostructures consisting of SmNiO3 and NdNiO3 alternating layers with additional LaAlO3 spacer layers were grown and fully characterized by means of x-ray diffraction, atomic force microscopy, and scanning transmission electron microscopy. A change in the orientation of the orthorhombic long-axis of the nickelate layers is observed when a single unit cell of LaAlO3 is inserted between SmNiO3 and NdNiO3, in agreement with density functional theory calculations. At the same time, the structure of the ultra-thin rhombohedral LaAlO3 layers is affected by their proximity to orthorhombic nickelate layers, with both scanning transmission electron microscopy studies and density functional theory calculations revealing a weak antipolar motion of the La-cation in the LaAlO3 layers that is not present in the bulk rhombohedral structure of this compound.

Lucia Varbaro, Bernat Mundet, Subhadeep Bandyopadhyay, Claribel Domínguez, Jennifer Fowlie, Lukas Korosec, Chih-Ying Hsu, Duncan T. L. Alexander, Philippe Ghosez, Jean-Marc Triscone
Varbaro et al. – APL Mater. 12, 031104 (2024)