Spin and orbital excitations in undoped infinite-layer superconducting PrNiO2 and insulating CaCuO2
Journal article, 2026
Infinite-layer nickelates are among the most promising cuprate-akin superconductors, although relevant differences from copper oxides have been reported. Here, we present momentum- and polarization-resolved RIXS measurements on nominally undoped, superconducting PrNiO2 , and compare its magnetic and orbital excitations with those of the reference infinite layer cuprate CaCuO2 . In PrNiO2 , the in-plane magnetic exchange integrals are smaller than in CaCuO2 , whereas the out-of-plane values are similar, indicating that both materials support three-dimensional antiferromagnetic correlations. Orbital excitations, associated to the transitions within 3d states of the metal, are well reproduced within a single-ion model and display similar characteristics, except the Ni-dxy peak that, besides lying at significantly lower energy, shows an opposite dispersion to that of Cu-dxy . We attribute this difference to the values of the orbital superexchange coupling between nearest neighbor sites. Our observations suggest that infinite-layer cuprates and nickelates share most of the spin and orbital properties, but in nickelates the larger charge-transfer energy Δ and smaller hopping integrals imply smaller spin-fluctuation energy and stronger localization of the doping charge on the metal site. https://doi.org/10.15151/ESRF-ES-1430231833.
Author
Francesco Rosa
University of Cologne
Polytechnic University of Milan
H. Sahib
IPCMS Institut de Physique et Chimie des Materiaux de Strasbourg
University of Halabja
Giacomo Merzoni
Polytechnic University of Milan
European XFEL
L. Martinelli
University of Zürich
Polytechnic University of Milan
Riccardo Arpaia
Universita Ca' Foscari Venezia
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Nicholas B. Brookes
European Synchrotron Radiation Facility (ESRF)
D. Di Castro
University of Rome Tor Vergata
K. Wohlfeld
University of Warsaw
Maryia Zinouyeva
Polytechnic University of Milan
Marco Salluzzo
National Research Council of Italy (CNR)
D. Preziosi
IPCMS Institut de Physique et Chimie des Materiaux de Strasbourg
Giacomo Ghiringhelli
Polytechnic University of Milan
Communications Materials
26624443 (eISSN)
Vol. 7 1 250Subject Categories (SSIF 2025)
Theoretical Chemistry
Condensed Matter Physics
DOI
10.1038/s43246-026-01266-y