Nickelate Superlattice Paper Published in Phys Rev Mater

Our team’s paper, led by Le Wang, was recently selected for an Editor’s Choice in Physical Review Materials! Harnessing the unique properties of Sr-doped nickelate thin films is challenging because of competing structural and chemical defects. We explore synthesis and stabilization of these materials, revealing tunable hole conductivity for emerging nickelate superconductors. This paper features our TEMWizard code for atomic-scale fitting using an intuitive GUI developed by Marjolein Oostrom.

From the abstract:

Sr doping in perovskite-structured rare-earth nickelates (RNiO3, where R denotes the lanthanide) has recently been widely studied to explore the resulting wide range of structural and physical properties. However, the substitution of Sr has been shown to induce local defects and structural instabilities as bulk SrNiO3 exhibits a hexagonal phase and is not stable. Thus, it is important to understand how to stabilize perovskite structured SrNiO3 and how the local charges are distributed in the lattice. Here, we report the deposition and characterization of a set of atomically precise (SrNiO3)1/(SrTiO3)n superlattices using oxide molecular beam epitaxy. We demonstrate that one unit cell of SrNiO3 can be stabilized as a perovskite in these structures and that there is no charge transfer across the heterointerface. Holes are confined to the SrNiO3 unit cells, resulting in a Ni valence between 3 and 4. Hole hopping conductivity is observed in the n = 1 superlattice but is strongly suppressed along the c-axis direction for n = 3 and 5, resulting in the insulting behavior in the latter. Our study will inspire the epitaxial synthesis of (SrNiO3)1/(RNiO3)n superlattices, as measurements of their properties could open a new platform for studying nickelate-based superconductors.

To view the manuscript, visit: https://doi.org/10.1103/PhysRevMaterials.6.075006

To download the article directly, click here.

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