Thickness-Dependent Interface Polarity in Infinite-Layer Nickelate Superlattices.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37027232.
- Also identified by DOI 10.1021/acs.nanolett.3c00192 and PMC identifier 10141440.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The interface polarity plays a vital role in the physical properties of oxide heterointerfaces because it can cause specific modifications of the electronic and atomic structure. Reconstruction due to the strong polarity of the NdNiO<sub>2</sub>/SrTiO<sub>3</sub> interface in recently discovered superconducting nickelate films may play an important role, as no superconductivity has been observed in the bulk. By employing four-dimensional scanning transmission electron microscopy and electron energy-loss spectroscopy, we studied effects of oxygen distribution, polyhedral distortion, elemental intermixing, and dimensionality in NdNiO<sub>2</sub>/SrTiO<sub>3</sub> superlattices grown on SrTiO<sub>3</sub> (001) substrates. Oxygen distribution maps show a gradual variation of the oxygen content in the nickelate layer. Remarkably, we demonstrate thickness-dependent interface reconstruction due to a polar discontinuity. An average cation displacement of ∼0.025 nm at interfaces in 8NdNiO<sub>2</sub>/4SrTiO<sub>3</sub> superlattices is twice larger than that in 4NdNiO<sub>2</sub>/2SrTiO<sub>3</sub> superlattices. Our results provide insights into the understanding of reconstructions at NdNiO<sub>2</sub>/SrTiO<sub>3</sub> polar interfaces.