Electronic structure of the parent compound of superconducting infinite-layer nickelates

• Published in: Nature materials Vol. 19; no. 4; pp. 381 - 385
• Main Authors: Hepting, M., Li, D., Jia, C. J., Lu, H., Paris, E., Tseng, Y., Feng, X., Osada, M., Been, E., Hikita, Y., Chuang, Y.-D., Hussain, Z., Zhou, K. J., Nag, A., Garcia-Fernandez, M., Rossi, M., Huang, H. Y., Huang, D. J., Shen, Z. X., Schmitt, T., Hwang, H. Y., Moritz, B., Zaanen, J., Devereaux, T. P., Lee, W. S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.04.2020; Nature Publishing Group; Springer Nature - Nature Publishing Group
• Subjects: 639/301; 639/766; Biomaterials; Chemistry and Materials Science; Condensed Matter Physics; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Copper compounds; Cuprates; Density functional theory; Earth; Electronic properties; Electronic structure; Electrons; Fermions; High temperature; High temperature superconductors; Letter; Materials Science; Nanotechnology; Nickel; Optical and Electronic Materials; Physics; Rare earth elements; Spectrum analysis; Superconductivity; X-ray spectroscopy
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-019-0585-z

The search continues for nickel oxide-based materials with electronic properties similar to cuprate high-temperature superconductors 1 – 10 . The recent discovery of superconductivity in the doped infinite-layer nickelate NdNiO 2 (refs. 11 , 12 ) has strengthened these efforts. Here, we use X-ray spectroscopy and density functional theory to show that the electronic structure of LaNiO 2 and NdNiO 2 , while similar to the cuprates, includes significant distinctions. Unlike cuprates, the rare-earth spacer layer in the infinite-layer nickelate supports a weakly interacting three-dimensional 5 d metallic state, which hybridizes with a quasi-two-dimensional, strongly correlated state with 3 d x 2 − y 2 symmetry in the NiO 2 layers. Thus, the infinite-layer nickelate can be regarded as a sibling of the rare-earth intermetallics 13 – 15 , which are well known for heavy fermion behaviour, where the NiO 2 correlated layers play an analogous role to the 4 f states in rare-earth heavy fermion compounds. This Kondo- or Anderson-lattice-like ‘oxide-intermetallic’ replaces the Mott insulator as the reference state from which superconductivity emerges upon doping. X-ray spectroscopy and density functional theory are used to show that the electronic structure of the parent compound of superconducting infinite-layer nickelates, while similar to the copper-based high-temperature superconductors, has significant differences.