Superconductivity in infinite-layer nickelate La 1-x Ca x NiO 2 thin films

• Published in: Science advances Vol. 8; no. 7; p. eabl9927
• Main Authors: Zeng, Shengwei, Li, Changjian, Chow, Lin Er, Cao, Yu, Zhang, Zhaoting, Tang, Chi Sin, Yin, Xinmao, Lim, Zhi Shiuh, Hu, Junxiong, Yang, Ping, Ariando, Ariando
• Format: Journal Article
• Language: English
• Published: United States 18.02.2022
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.abl9927

We report the observation of superconductivity in infinite-layer Ca-doped LaNiO (La Ca NiO ) thin films and construct their phase diagram. Unlike the metal-insulator transition in Nd- and Pr-based nickelates, the undoped and underdoped La Ca NiO thin films are entirely insulating from 300 K down to 2 K. A superconducting dome is observed at 0.15 < < 0.3 with weakly insulating behavior at the overdoped regime. Moreover, the sign of the Hall coefficient changes at low temperature for samples with a higher doping level. However, distinct from the Nd- and Pr-based nickelates, the -sign-change temperature remains at around 35 K as the doping increases, which begs further theoretical and experimental investigation to reveal the role of the 4f orbital to the (multi)band nature of the superconducting nickelates. Our results also emphasize a notable role of lattice correlation on the multiband structures of the infinite-layer nickelates.