Origin of a Topotactic Reduction Effect for Superconductivity in Infinite-Layer Nickelates

Origin of a Topotactic Reduction Effect for Superconductivity in Infinite-Layer Nickelates

Physical Review Letters

10.1103/PhysRevLett.133.066503

https://doi.org/10.1103/physrevlett.133.066503

Shengwei Zeng, Chi Sin Tang, Zhaoyang Luo, Lin Er Chow, Zhi Shiuh Lim, Saurav Prakash, Ping Yang, Caozheng Diao, Xiaojiang Yu, Zhenxiang Xing, Rong Ji, Xinmao Yin, Changjian Li, X. Renshaw Wang, Qian He, Mark B. H. Breese, A. Ariando, Huajun Liu

08 August 2024

Zeng, S., Tang, C. S., Luo, Z., Chow, L. E., Lim, Z. S., Prakash, S., Yang, P., Diao, C., Yu, X., Xing, Z., Ji, R., Yin, X., Li, C., Wang, X. R., He, Q., Breese, M. B. H., Ariando, A., & Liu, H. (2024). Origin of a Topotactic Reduction Effect for Superconductivity in Infinite-Layer Nickelates. Physical Review Letters, 133(6). https://doi.org/10.1103/physrevlett.133.066503

Topotactic reduction utilizing metal hydrides as reagents emerges as an effective approach to achieve exceptionally low oxidization states of metal ions and unconventional coordination networks. This method opens avenues to the development of entirely new functional materials, with one notable example being the infinite-layer nickelate superconductors. However, the reduction effect on the atomic reconstruction and electronic structures – crucial for superconductivity – remains largely unresolved. We design two sets of control Nd0.8Sr0.2NiO2 thin films and implement secondary ion mass spectroscopy to highlight the absence of reduction-induced hydrogen intercalation. X-ray absorption spectroscopy shows a significant linear dichroism with dominant Ni 3dx2-y2 orbitals on superconducting samples, indicating a Ni single-band nature of infinite-layer nickelates. Consistent with the superconducting Tc, the Ni 3d orbitals asymmetry manifests a dome-like reduction duration dependence. Our results unveil the critical role of reduction in modulating the Ni-3d orbital polarization and its impact on the superconducting properties.

Publisher Copyright

This research / project is supported by the Agency for Science, Technology and Research - RIE2025 Manufacturing, Trade, and Connectivity Individual Research Grants
Grant Reference no. : M22K2c0084

This research / project is supported by the National Research Foundation - Competitive Research Program
Grant Reference no. : NRF-CRP28-2022-0002

This research / project is supported by the Agency for Science, Technology and Research - Career Development Fund
Grant Reference no. : C210812020

This research / project is supported by the Agency for Science, Technology and Research - Central Research Fund
Grant Reference no. :

This research / project is supported by the Ministry of Education, Singapore - Academic Research Fund (AcRF) Tier 2
Grant Reference no. : MOE-T2EP50121-0018, MOE-T2EP50123-0013, MOE-T2EP50120-0006

This research / project is supported by the National Research Foundation - NRF-ISF Joint Program
Grant Reference no. : NRF2020-NRF-ISF004-3518

For the publisher's version, please refer here: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.066503

https://oar.a-star.edu.sg/communities-collections/articles/21853

0031-9007
1079-7114

Institute of Materials Research & Engineering