The discovery of superconductivity in infinite-layer nickelates has opened a new frontier in the study of unconventional superconductors, offering a platform to explore superconductivity beyond the well-established cuprate paradigm. Nickelate superconductors share key structural motifs with cuprates, most notably the quasi-two-dimensional NiO₂ planes of the infinite-layer structure. However, they also exhibit significant differences in electronic structure, orbital character, and charge-transfer energy. These distinctions place nickelates in an intermediate regime between Mott–Hubbard and Hund’s metal physics, giving rise to unconventional pairing mechanisms that remain under active investigation.
In this talk, I will review the structural characteristics common to all classes of unconventional superconductors, with particular emphasis on close-packed architectures. I will then present recent results on established nickelate compounds that reveal previously overlooked structural peculiarities. Building on these insights, I will introduce new candidate nickelate materials and compare their deviations. Finally, I conclude with a discussion of material design strategies aimed at guiding the discovery and optimization of future unconventional superconductors.