Atomic Lattice and Electronic Structure of Superconducting Nickelate Thin Films*

The recent discovery of superconductivity in Sr-doped NdNiO₂ is an important development for condensed matter physics [1]. Nominally similar in structure to the infinite-layer cuprate superconductors, the nickelates present a complementary platform for investigating the underlying physical mechanisms driving superconductivity in these systems. The stabilization of superconducting samples is, however, as yet limited to thin film geometries, raising the importance of spatially localized characterization techniques capable of probing only the regions of interest without contributions from the substrate. Here, we harness the high spatial and energy resolution achieved with scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) to explore both the lattice and electronic structure of these superconducting thin films. Structurally, the effects of different growth parameters are explored across several films within the nickelate series. Electronically, we investigate possible similarities to the cuprate superconductors.

[1] Li, et al. Nature 572, 624 (2019).