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Abstract The occurrence of unconventional superconductivity in cuprates has long motivated the search for manifestations in other layered transition metal oxides. Recently, superconductivity is found in infinite‐layer nickelate (Nd,Sr)NiO2and (Pr,Sr)NiO2thin films, formed by topotactic reduction from the perovskite precursor phase. A topic of much current interest is whether rare‐earth moments are essential for superconductivity in this system. In this study, it is found that with significant materials optimization, substantial portions of the La1−xSrxNiO2phase diagram can enter the regime of coherent low‐temperature transport (x = 0.14 ‐ 0.20), with subsequent superconducting transitions and a maximum onset of ≈9 K atx = 0.20. Additionally, the unexpected indication of a superconducting ground state in undoped LaNiO2is observed, which likely reflects the self‐doped nature of the electronic structure. Combining the results of (La/Pr/Nd)1−xSrxNiO2reveals a generalized superconducting dome, characterized by systematic shifts in the unit cell volume and in the relative electron‐hole populations across the lanthanides.
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This content will become publicly available on December 1, 2025
Extensive hydrogen incorporation is not necessary for superconductivity in topotactically reduced nickelates
Abstract A key open question in the study of layered superconducting nickelate films is the role that hydrogen incorporation into the lattice plays in the appearance of the superconducting state. Due to the challenges of stabilizing highly crystalline square planar nickelate films, films are prepared by the deposition of a more stable parent compound which is then transformed into the target phaseviaa topotactic reaction with a strongly reducing agent such as CaH2. Recent studies, both experimental and theoretical, have introduced the possibility that the incorporation of hydrogen from the reducing agent into the nickelate lattice may be critical for the superconductivity. In this work, we use secondary ion mass spectrometry to examine superconducting La1−xXxNiO2/ SrTiO3(X= Ca and Sr) and Nd6Ni5O12/ NdGaO3films, along with non-superconducting NdNiO2/ SrTiO3and (Nd,Sr)NiO2/ SrTiO3. We find no evidence for extensive hydrogen incorporation across a broad range of samples, including both superconducting and non-superconducting films. Theoretical calculations indicate that hydrogen incorporation is broadly energetically unfavorable in these systems, supporting our conclusion that extensive hydrogen incorporation is not generally required to achieve a superconducting state in layered square-planar nickelates.
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- PAR ID:
- 10543477
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Springer Nature
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 15
- Issue:
- 1
- ISSN:
- 2041-1723
- Page Range / eLocation ID:
- 7387
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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