Li Danfeng, Wang Bai Yang, Lee Kyuho, Harvey Shannon P, Osada Motoki, Goodge Berit H, Kourkoutis Lena F, Hwang Harold Y
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
Phys Rev Lett. 2020 Jul 10;125(2):027001. doi: 10.1103/PhysRevLett.125.027001.
We report the phase diagram of Nd_{1-x}Sr_{x}NiO_{2} infinite layer thin films grown on SrTiO_{3}. A superconducting dome spanning 0.125<x<0.25 is found, remarkably similar to cuprates, albeit over a narrower doping window. However, while cuprate superconductivity is bounded by an insulator for underdoping and a metal for overdoping, here we observe weakly insulating behavior on either side of the dome. Furthermore, the normal state Hall coefficient is always small and proximate to a continuous zero crossing in doping and in temperature, in contrast to the ∼1/x dependence observed for cuprates. This suggests the presence of both electronlike and holelike bands, consistent with band structure calculations.
我们报道了在SrTiO₃上生长的Nd₁₋ₓSrₓNiO₂无限层薄膜的相图。发现了一个超导穹顶,其范围为0.125 < x < 0.25,与铜酸盐非常相似,尽管掺杂窗口更窄。然而,虽然铜酸盐超导在欠掺杂时由绝缘体界定,在过掺杂时由金属界定,但在这里我们在穹顶的两侧都观察到了弱绝缘行为。此外,与铜酸盐中观察到的~1/x依赖性相反,正常态霍尔系数总是很小,并且在掺杂和温度方面接近连续的零交叉。这表明存在电子型和空穴型能带,与能带结构计算一致。