Strong Superexchange in a $d^{9-δ}$ Nickelate Revealed by Resonant Inelastic X-Ray Scattering
J. Q. Lin, P. Villar Arribi, G. Fabbris, A. S. Botana, D. Meyers, H. Miao, Y. Shen, D. G. Mazzone, J. Feng, S. G. Chiuzbaian, A. Nag, A. C. Walters, M. Garcia-F… 展开作者
J. Q. Lin, P. Villar Arribi, G. Fabbris, A. S. Botana, D. Meyers, H. Miao, Y. Shen, D. G. Mazzone, J. Feng, S. G. Chiuzbaian, A. Nag, A. C. Walters, M. Garcia-Fernandez, Ke-Jin Zhou, J. Pelliciari, I. Jarrige, J. W. Freeland, Junjie Zhang, J. F. Mitchell, V. Bisogni, X. Liu, M. R. Norman, M. P. M. Dean
备注：
7 pages not including supplmentary material; To appear in Physical Review Letters
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 trilayer nickelate $d^{9-1/3}$ La4Ni3O8 and associated theoretical modeling. A magnon energy scale of ~80 meV resulting from a nearest-neighbor magnetic exchange of $J = 69(4)4$ 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, and suggests that they represent a promising route towards higher-temperature nickelate superconductivity.
We give a brief review of the Mott-Kondo scenario and its consequence in the recently-discovered infinite-layer nickelate superconductors. We argue that the parent state is a self-doped Mott insulator and propose an effective $t$-$J$-$K$ model to account for its low-energy properties. At small doping, the model describes a low carrier density Kondo system with incoherent Kondo scattering at finite temperatures, in good agreement with experimental observation of the logarithmic temperature dependence of electric resistivity. Upon increasing Sr doping, the model predicts a breakdown of the Kondo…
Theoretical investigation of superconductivity in trilayer square-planar nickelates
Sr掺杂的NdNiO $_{2}$超导性的发现是对具有与铜酸盐类似的电子和磁性的氧化镍材料的长期追求的关键突破。NdNiO $_2$是一种具有一般化学式R $_{n+1}$ Ni $_n$ O $_{2n+2}$（R = La，Pr，Nd，$n= 2, 3, ... \infty$）的正方形平面镍酸盐家族的无限层成员。在这封信中，我们调查的三层成员的超导电性，这一系列（R $_4$ Ni $_3$ O $_8$）使用第一性原理和$t-J$模型计算相结合。RPDMATHABMS Ni $_3$ O $_8$化合物比RNiO $_2$材料更类似于铜酸盐，因为只有Ni- $d_{x^{2}-y^{2}}$带穿过费米能级，它们表现出大大降低的电荷转移能量，因此超交换相互作用显著增强。我们发现，掺杂R-$_4$-Ni-$_3$-O-$_8$化合物的超导不稳定性比掺杂Sr-$_{0.2}$-Nd-$_{0.8}$-Ni-O-$_2$化合物的超导不稳定性强得多，其最大禁带宽度约为掺杂Sr-$_{0.2}$-Nd-$_{0.8}$-Ni-$_2$化合物的四倍。
The discovery of superconductivity in square-planar low valence nickelates has ignited a vigorous debate regarding their essential electronic properties: Do these materials have appreciable oxygen charge-transfer character akin to the cuprates, or are they in a distinct Mott-Hubbard regime where oxygen plays a minimal role? Here, we resolve this question using O $K$-edge resonant inelastic x-ray scattering (RIXS) measurements of the low valence nickelate La$_{4}$Ni$_{3}$O$_{8}$ and a prototypical cuprate La$_{2-x}$Sr$_{x}$CuO$_{4}$ ($x=0.35$). As expected, the cuprate lies deep in the charge-t…
Low-valence nickelates $-$ including infinite-layer (IL) and trilayer (TL) compounds $-$ are longstanding candidates for mimicking the high-temperature superconductivity of cuprates. A recent breakthrough in the field came with the discovery of superconductivity in hole-doped IL nickelates. Yet, the degree of similarity between low-valence nickelates and cuprates is the subject of a profound debate for which soft x-ray spectroscopy experiments at the Ni $L$- and O $K$-edge provided critical input. In this review, we will discuss the essential elements of the electronic structure of low-valance…
The discovery of superconductivity in infinite-layer nickelates brings us tantalizingly close to a new material class that mirrors the cuprate superconductors. Here, we report on magnetic excitations in these nickelates, measured using resonant inelastic x-ray scattering (RIXS) at the Ni L3-edge, to shed light on the material complexity and microscopic physics. Undoped NdNiO2 possesses a branch of dispersive excitations with a bandwidth of approximately 200 meV, reminiscent of strongly-coupled, antiferromagnetically aligned spins on a square lattice, despite a lack of evidence for long range m…
Strongly correlated materials often respond sensitively to the external perturbations. In the recently discovered superconducting infinite-layer nickelates, the superconducting transition temperature can be dramatically enhanced via only ~1% compressive strain-tuning enabled by substrate design. However, the root of such enhancement remains elusive. While the superconducting pairing mechanism is still not settled, magnetic Cooper pairing - similar to the cuprates has been proposed. Using resonant inelastic x-ray scattering, we investigate the magnetic excitations in infinite-layer PrNiO2 thin …
Charge order is a central feature of the physics of cuprate superconductors and is known to arise from a modulation of holes with primarily oxygen character. Low-valence nickelate superconductors also host charge order, but the electronic character of this symmetry breaking is unsettled. Here, using resonant inelastic x-ray scattering at the Ni $L_2$-edge, we identify intertwined involvements of Ni $3d_{x^2-y^2}$, $3d_{3z^2-r^2}$, and O $2p_σ$ orbitals in the formation of diagonal charge order in an overdoped low-valence nickelate La$_{4}$Ni$_{3}$O$_{8}$. The Ni $3d_{x^2-y^2}$ orbitals, strong…
Dissecting superconductivity in the Ruddlesden-Popper nickelates: The role of electron correlation and interlayer magnetic exchange
Diamond Light Source（钻石光源）；National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China（中国科学技术大学核科学与技术学院/国家同步辐射实验室）；Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-Sen University（中山大学物理学院/广东省铁电与磁器件重点实验室）；Department of Physics, University of Oxford（牛津大学物理系）；National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University（南京大学固体微结构物理国家重点实验室/物理学院）；Collaborative Innovation Center of Advanced Microstructures, Nanjing University（南京大学先进微结构协同创新中心）
Observation of correlated plasmons in low-valence nickelates
Brookhaven National Laboratory（布鲁克海文国家实验室）；Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所凝聚态物理北京国家实验室）；Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory（斯坦福材料能源科学研究所，SLAC国家加速器实验室）；National Synchrotron Light Source II, Brookhaven National Laboratory（布鲁克海文国家实验室第二代同步辐射光源）；Shanghai Advanced Research in Physical Sciences (SHARPS)（上海物理科学研究前沿中心）
Lattice-charge coupling in a trilayer nickelate with intertwined density wave order
Argonne National Laboratory（阿贡国家实验室）；Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）；Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所）；Brookhaven National Laboratory（布鲁克海文国家实验室）；Center for Computational Quantum Physics, Flatiron Institute（平顿研究院计算量子物理中心）；Arizona State University（亚利桑那州立大学）；Southeast University（东南大学）；Shandong University（山东大学）；Northwestern University（西北大学）
Contrasting Spin Excitations in Octahedral and Square-Planar n=8 Ruddlesden-Popper Nickelates
Yale University（耶鲁大学）；Flatiron Institute（平顿研究所）；Harvard University（哈佛大学）；Donostia International Physics Center (DIPC)（多诺斯蒂亚国际物理中心）；University of California San Diego（加利福尼亚大学圣迭戈分校）；European Synchrotron Radiation Facility（欧洲同步辐射装置）
The recent discovery of superconductivity in Nd$_{1-x}$Sr$_{x}$NiO$_2$ has drawn significant attention in the field. A key open question regards the evolution of the electronic structure with respect to hole doping. Here, we exploit x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS) to probe the doping dependent electronic structure of the NiO$_2$ planes. Upon doping, a higher energy feature in Ni $L_3$ edge XAS develops in addition to the main absorption peak. By comparing our data to atomic multiplet calculations including $D_{4h}$ crystal field, the doping in…
Universal orbital and magnetic structures in infinite-layer nickelates
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory（斯坦福材料能源科学研究所，SLAC国家加速器实验室）；Department of Physics, Stanford University（斯坦福大学物理系）；School of Applied and Engineering Physics, Cornell University（康奈尔大学应用工程物理学院）；Kavli Institute at Cornell for Nanoscale Technology, Cornell University（康奈尔大学纳米技术卡弗里研究所）；Diamond Light Source（钻石光源）；Department of Materials Science and Engineering, Stanford University（斯坦福大学材料科学与工程系）
A unified theory of thin film and bulk bilayer nickelates
School of Physics, Hangzhou Normal University（杭州师范大学物理学院）；Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所北京凝聚态物理国家研究中心）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）
Motivated by the recent X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) experiments, we use a detailed impurity model to explore the nature of the parent compound and hole doped states of (La, Nd, Pr)NiO$_2$ by including the crystal field splitting, the Ni-$3d$ multiplet structure, and the hybridization between Ni-$3d$, O-$2p$, and Nd-$5d$ orbitals. For simplicity and stimulated by the recent electronic structure calculations, the latter are formally replaced with symmetric orbitals centered at the missing O sites in the Nd layer, forming a two-dimensional (2…
Multiorbital Anisotropy and Magnetic Excitations in Trilayer Nickelate Pr$_4$Ni$_3$O$_{10}$
Harvard University（哈佛大学）；Brookhaven National Laboratory（布鲁克海文国家实验室）；Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory（SLAC国家加速器实验室斯坦福材料与能源科学研究所）；European Synchrotron Radiation Facility（欧洲同步辐射装置）；Argonne National Laboratory（阿贡国家实验室）
Spin and orbital excitations in undoped infinite layers: a comparison between superconducting PrNiO2 and insulating CaCuO2
Politecnico di Milano（米兰理工大学）；University of Cologne（科隆大学）；Université de Strasbourg（斯特拉斯堡大学）；European XFEL（欧洲X射线自由电子激光装置）；Ca’ Foscari University of Venice（威尼斯卡福斯卡里大学）；Chalmers University of Technology（查尔姆斯理工大学）；ESRF, The European Synchrotron（欧洲同步辐射装置）；Università di Roma Tor Vergata（罗马托维爾加塔大学）
$3d_{z^2}$ orbital delocalization and magnetic collapse in superconducting (La,Pr)$_3$Ni$_2$O$_{7-δ}$ films
Diamond Light Source（钻石光源）；National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China（中国科学技术大学核科学与技术学院和同步辐射实验室）；Southern University of Science and Technology（南方科技大学）；Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所和北京凝聚态物理国家研究中心）；University of Chinese Academy of Sciences（中国科学院大学）；Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area（粤港澳大湾区量子科学中心）
Filling and Interlayer Superexchange Control Superconductivity in La$_3$Ni$_2$O$_7$
School of Physics, Beijing Institute of Technology（北京理工大学物理学院）；Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）；Zhejiang Key Laboratory of Quantum State Control and Optical Field Manipulation, Department of Physics, Zhejiang Sci-Tech University（浙江理工大学物理学院）
Correlation of the Superconducting Critical Temperature with Spin and Orbital Excitation Energies In (Ca{x}La{1-x})(Ba{1.75-x}La{0.25+x})Cu{3}O{y} as Measured by Resonant Inelastic X-ray Scattering
Superconductivity in infinite-layer nickelates holds exciting analogies with that of cuprates, with similar structures and $3d$-electron count. Using resonant inelastic x-ray scattering (RIXS) we studied electronic and magnetic excitations and charge density correlations in Nd$_{1-x}$Sr$_{x}$NiO$_2$ thin films with and without an SrTiO$_3$ capping layer. We observe dispersing magnons only in the capped samples, progressively dampened at higher doping. In addition, we detect an elastic resonant scattering peak in the uncapped $x=0$ compound at wave vector (1/3,0), remindful of the charge order …
