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# Superconductivity in a quintuple-layer square-planar nickelate

## Abstract

Since the discovery of high-temperature superconductivity in copper oxide materials1, there have been sustained efforts to both understand the origins of this phase and discover new cuprate-like superconducting materials2. One prime materials platform has been the rare-earth nickelates and, indeed, superconductivity was recently discovered in the doped compound Nd0.8Sr0.2NiO2 (ref. 3). Undoped NdNiO2 belongs to a series of layered square-planar nickelates with chemical formula Ndn+1NinO2n+2 and is known as the ‘infinite-layer’ (n = ) nickelate. Here we report the synthesis of the quintuple-layer (n = 5) member of this series, Nd6Ni5O12, in which optimal cuprate-like electron filling (d8.8) is achieved without chemical doping. We observe a superconducting transition beginning at ~13 K. Electronic structure calculations, in tandem with magnetoresistive and spectroscopic measurements, suggest that Nd6Ni5O12 interpolates between cuprate-like and infinite-layer nickelate-like behaviour. In engineering a distinct superconducting nickelate, we identify the square-planar nickelates as a new family of superconductors that can be tuned via both doping and dimensionality.

## Relevant articles

• ### Pressure-induced monotonic enhancement of Tc to over 30 K in superconducting Pr0.82Sr0.18NiO2 thin films

Nature Communications Open Access 28 July 2022

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## Data availability

The data supporting the findings of this study are available from the corresponding authors upon reasonable request. Source data for Figs. 24 are provided with this paper.

## References

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## Acknowledgements

We thank M. R. Norman and M. Mitrano for discussions. We also thank K. Lee and H. Y. Hwang for discussions and technical guidance in reduction experiments; D. Erdosy, J. Lee, N. Pappas, S. Thapa and M. Wenny for continued support in reductions; H. Hijazi at the Rutgers University Laboratory of Surface Modification for assistance in Rutherford backscattering spectrometry; and J. MacArthur for electronics support. This research was funded in part by the Gordon and Betty Moore Foundation’s EPiQS Initiative, grant no. GBMF6760 to J. A. Mundy. Materials growth and electron microscopy were supported in part by the Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials (PARADIM) under NSF Cooperative Agreement no. DMR-2039380. Electron microscopy made use of the Cornell Center for Materials Research (CCMR) Shared Facilities, which are supported through the NSF MRSEC Program (no. DMR-1719875). The Thermo Fisher Spectra 300 X-CFEG was acquired with support from PARADIM, an NSF MIP (DMR-2039380) and Cornell University. Nanofabrication work was performed in part at Harvard University’s Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), supported by the National Science Foundation under NSF grant no. 1541959, and in part at the University of Michigan Lurie Nanofabrication Facility. This research used resources of the Advanced Light Source, a US DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. G.A.P. acknowledges support from the Paul & Daisy Soros Fellowship for New Americans and from the NSF Graduate Research Fellowship grant no. DGE-1745303. G.A.P. and D.F.S. acknowledge support from US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under award no. DE-SC0021925. Q.S., S.D. and D.C.C. were supported by the STC Center for Integrated Quantum Materials, NSF grant no. DMR-1231319. B.H.G., H.P. and L.F.K. acknowledge support by PARADIM, NSF no. DMR-2039380. A.T.P. acknowledges support from the Department of Defense through the National Defense Science and Engineering Graduate Fellowship (NDSEG) Program. J. A. Mason acknowledges support from the Arnold and Mabel Beckman Foundation through a Beckman Young Investigator grant. O.E. acknowledges support from NSF grant no. DMR-1904716. A.S.B. and H.L. acknowledge NSF grant no. DMR-2045826 and the ASU Research Computing Center for HPC resources. J. A. Mundy acknowledges support from the Packard Foundation.

## Author information

Authors

### Contributions

G.A.P., Q.S., C.M.B. and J. A. Mundy synthesized the thin films with assistance from H.P. G.A.P., D.F.S. and S.D. conducted the reductions with guidance from J. A. Mason. B.H.G. and L.F.K. characterized the samples with scanning transmission electron microscopy. G.A.P., A.T.P. and A.Y. performed transport measurements using fabrication assistance from S.N. and J.T.H. G.A.P., D.F.S., Q.S., D.C.C., A.T.N. and P.S. performed X-ray absorption spectroscopy. H.L. and A.S.B. performed density functional theory calculations. E.M.N., O.E. and A.S.B. constructed the tJ model. A.S.B. and J. A. Mundy conceived and guided the study. G.A.P., A.S.B. and J. A. Mundy wrote the manuscript with discussion and contributions from all authors.

### Corresponding authors

Correspondence to Antia S. Botana or Julia A. Mundy.

## Ethics declarations

### Competing interests

The authors declare no competing interests.

Peer review information Nature Materials thanks Hai-Hu Wen and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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## Supplementary information

### Supplementary information

Supplementary Table 1, Figs. 1–15 and Notes 1–6.

### Source Data Fig. 2

X-ray diffraction spectra.

### Source Data Fig. 3

Temperature dependence of electrical resistivities and Hall coefficients.

### Source Data Fig. 4

Band structure diagrams.

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Pan, G.A., Ferenc Segedin, D., LaBollita, H. et al. Superconductivity in a quintuple-layer square-planar nickelate. Nat. Mater. 21, 160–164 (2022). https://doi.org/10.1038/s41563-021-01142-9

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• DOI: https://doi.org/10.1038/s41563-021-01142-9

• ### Pressure-induced monotonic enhancement of Tc to over 30 K in superconducting Pr0.82Sr0.18NiO2 thin films

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