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
Department of Physics, Faculty of Science, National University of Singapore, Singapore 117551, Singapore.
Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore.
Sci Adv. 2022 Feb 18;8(7):eabl9927. doi: 10.1126/sciadv.abl9927.
We report the observation of superconductivity in infinite-layer Ca-doped LaNiO (LaCaNiO) thin films and construct their phase diagram. Unlike the metal-insulator transition in Nd- and Pr-based nickelates, the undoped and underdoped LaCaNiO 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.
我们报道了在无限层钙掺杂的镧镍氧化物（LaCaNiO）薄膜中观察到超导现象，并构建了它们的相图。与钕基和镨基镍酸盐中的金属-绝缘体转变不同，未掺杂和欠掺杂的LaCaNiO薄膜从300 K到2 K完全绝缘。在0.15 < < 0.3范围内观察到一个超导穹顶，在过掺杂区域呈现弱绝缘行为。此外，对于较高掺杂水平的样品，霍尔系数 的符号在低温下会发生变化。然而，与钕基和镨基镍酸盐不同的是，随着掺杂增加， -符号变化温度保持在35 K左右，这需要进一步的理论和实验研究来揭示4f轨道对超导镍酸盐（多）能带性质的作用。我们的结果还强调了晶格关联在无限层镍酸盐多能带结构上的显著作用。
