Abstract
The discovery of superconductivity in a d9-δ nickelate has inspired disparate theoretical perspectives regarding the essential physics of this class of materials. A key issue is the magnitude of the magnetic superexchange, which relates to whether cuprate-like high-temperature nickelate superconductivity could be realized. We address this question using Ni L-edge and O K-edge spectroscopy of the reduced d9-1/3 trilayer nickelates R4Ni3O8 (where R=La, Pr) and associated theoretical modeling. A magnon energy scale of ∼80 meV resulting from a nearest-neighbor magnetic exchange of J=69(4) meV is observed, proving that d9-δ nickelates can host a large superexchange. This value, along with that of the Ni-O hybridization estimated from our O K-edge data, implies that trilayer nickelates represent an intermediate case between the infinite-layer nickelates and the cuprates. Layered nickelates thus provide a route to testing the relevance of superexchange to nickelate superconductivity.
| Original language | English |
|---|---|
| Article number | 087001 |
| Journal | Physical Review Letters |
| Volume | 126 |
| Issue number | 8 |
| DOIs | |
| State | Published - Feb 22 2021 |
Funding
X-ray scattering work at Brookhaven National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-SC0012704. Work in the Materials Science Division of Argonne National Laboratory (crystal growth, characterization, and theoretical calculations) was sponsored by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. X. L. and J. Q. L. were supported by the ShanghaiTech University startup fund, MOST of China under Grant No. 2016YFA0401000, NSFC under Grant No. 11934017, and the Chinese Academy of Sciences under Grant No. 112111KYSB20170059. A. B. acknowledges the support from NSF DMR No. 2045826 and the ASU Research Computing Center for HPC resources. We acknowledge Diamond Light Source for time on Beamline I21 under Proposal 22261 producing the data shown in Fig. . This research used resources at the SIX beamline of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. We acknowledge Synchrotron SOLEIL for provision of synchrotron radiation facilities at the SEXTANTS beamline.