Lin J Q, Villar Arribi P, Fabbris G, Botana A S, Meyers D, Miao H, Shen Y, Mazzone D G, Feng J, Chiuzbăian S G, Nag A, Walters A C, García-Fernández M, Zhou Ke-Jin, Pelliciari J, Jarrige I, Freeland J W, Zhang Junjie, Mitchell J F, Bisogni V, Liu X, Norman M R, Dean M P M
Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
Phys Rev Lett. 2021 Feb 26;126(8):087001. doi: 10.1103/PhysRevLett.126.087001.
The discovery of superconductivity in a d^{9-δ} nickelate has inspired disparate theoretical perspectives regarding the essential physics of this class of materials. A key issue is the magnitude of the magnetic superexchange, which relates to whether cuprate-like high-temperature nickelate superconductivity could be realized. We address this question using Ni L-edge and O K-edge spectroscopy of the reduced d^{9-1/3} trilayer nickelates R_{4}Ni_{3}O_{8} (where R=La, Pr) and associated theoretical modeling. A magnon energy scale of ∼80 meV resulting from a nearest-neighbor magnetic exchange of J=69(4) meV is observed, proving that d^{9-δ} nickelates can host a large superexchange. This value, along with that of the Ni-O hybridization estimated from our O K-edge data, implies that trilayer nickelates represent an intermediate case between the infinite-layer nickelates and the cuprates. Layered nickelates thus provide a route to testing the relevance of superexchange to nickelate superconductivity.
在d⁹⁻δ镍酸盐中发现超导现象，引发了关于这类材料基本物理性质的不同理论观点。一个关键问题是磁超交换的强度，这与是否能实现类似铜酸盐的高温镍酸盐超导性有关。我们使用还原后的d⁹⁻¹/₃三层镍酸盐R₄Ni₃O₈（其中R = La、Pr）的Ni L边和O K边光谱以及相关的理论模型来解决这个问题。观察到由J = 69(4) meV的最近邻磁交换产生的约80 meV的磁振子能量尺度，证明d⁹⁻δ镍酸盐可以承载较大的超交换。这个值，连同我们从O K边数据估计的Ni - O杂化值，意味着三层镍酸盐代表了无限层镍酸盐和铜酸盐之间的中间情况。因此，层状镍酸盐为测试超交换与镍酸盐超导性的相关性提供了一条途径。
