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Daily Overview: Today’s research highlights in the field of nickelate superconductors focus on the regulation of oxygen content in the La₃Ni₂O₇₊δ system. A collaborative team from the Chinese Academy of Sciences, Hainan University, Sun Yat-sen University, and other institutions successfully isolated pure bilayer phases, hybrid 1212 phases, and triple-layer intergrowth phases with different structures by precisely controlling the oxygen content. They found significant differences in superconducting transition temperatures—the pure bilayer phase reaches approximately 83.5 K, while the triple-layer intergrowth phase only exhibits 4–6 K. The study also established a phase diagram showing the evolution of Tc and upper critical field Hc₂ with oxygen content, revealing the decisive influence of oxygen content on the intergrowth structure of Ruddlesden-Popper phases and superconducting properties. This work provides key experimental evidence for understanding the high-temperature superconducting mechanism and synthesis control of La₃Ni₂O₇₊δ. ...

Daily Overview: Today’s overview of the nickelate superconductor field focuses on magnetic studies of bilayer La₃Ni₂O₇ single crystals. Using neutron scattering techniques, this work, for the first time under ambient pressure, clarifies the spin excitation energy gap, in-plane anisotropic dispersion, and bilayer periodic modulation in this material, directly confirming the existence of interlayer antiferromagnetic coupling. A bilayer Heisenberg model based on stripe-type magnetic order successfully describes the experimental dispersion and reveals that its spin-wave bandwidth is only about 25% of that in cuprates, yet the total fluctuating magnetic moment at comparable energies is similar to that in cuprates, establishing a magnetic framework distinct from cuprates. These results provide key constraints on the magnetic order and spin dynamics for understanding the possible high-temperature superconductivity mechanism in bilayer nickelate systems. ...

Daily Overview: Here is the English translation of the provided Chinese daily paper overview: > — > Today’s Research Overview in the Nickelate Superconductor Field > Two research works today deepen our understanding of the superconducting mechanism in layered nickel oxides from the perspectives of structural and electronic phase transitions, as well as the relationship between electronic ordered phases and superconductivity. > First, a team from Université Paris-Saclay and other institutions systematically mapped the temperature-pressure phase diagram of the bilayer nickelate La₃Ni₂O₇ using high-pressure high-temperature Raman and infrared spectroscopy. They discovered that a pressure-induced lattice tilt-to-untilt structural phase transition is accompanied by a nearly two-order-of-magnitude increase in carrier concentration, and superconductivity is observed near the phase boundary. This work establishes a direct link between structural and electronic property changes, providing a key experimental foundation for understanding its high-pressure superconducting mechanism. > Meanwhile, another study led by Brookhaven National Laboratory and other institutions focuses on bilayer nickelate La₂PrNi₂O₇ thin films. Using resonant X-ray scattering and spectroscopy, they provide strong evidence that the spin density wave (SDW) is not a precursor state of superconductivity but rather a competing phase associated with oxygen vacancies. The work further proposes that in the superconducting phase, regions with intact oxygen stoichiometry have a ground state characterized by robust interlayer five-spin polaron states, which lock out-of-plane orbitals and render the in-plane orbital behavior close to the classical electronic configuration of cuprates and infinite-layer nickelates. > In summary, these studies not only elucidate the structural origin of pressure-driven superconductivity but also reveal the key regulatory role of oxygen stoichiometry in electronic states and the superconducting/competing phase balance, offering new perspectives for exploring the microscopic mechanism of nickelate superconductivity. ...

Daily Overview: Based on the list of papers you provided, no research papers directly focusing on nickel-based superconductivity as the core topic were found in today’s overview. Therefore, in accordance with your requirements, a related overall introduction cannot be generated this time. 1. Dimensionality-Driven Electronic and Orbital Transitions Mediating Interfacial Magnetism in LaNiO3/CaMnO3 Observed In Situ Relevance Score: 4.9295 Authors: B-A. Courchene, A. Hampel, S. Beck, J. R. Paudel, J. D. Grassi, L. A. Lapinski, A. M. Derrico, M. Terilli, M. Kareev, C. Klewe, A. Gloskovskii, C. Schlueter, S. K. Chaluvadi, F. Mazzola, I. Vobornik, P. Orgiani, J. Chakhalian, A. J. Millis, A. X. Gray Affiliations: University of California, Berkeley, Lawrence Berkeley National Laboratory, DESY, Temple University, AREA Science Park, Rutgers University, CNR-IOM, Cornell University, Università degli Studi di Padova, Columbia University, Flatiron Institute Link: http://arxiv.org/abs/2604.28054v1 Summary: This study systematically investigates the modulation of interfacial magnetism by dimension-driven electronic and orbital transitions in LaNiO₃/CaMnO₃ superlattices through a combination of in-situ synthesis, polarization-dependent angle-resolved photoelectron spectroscopy, X-ray magnetic circular dichroism, and first-principles electronic structure calculations. It is found that reducing the LaNiO₃ thickness to the ultrathin limit triggers a metal-insulator transition, accompanied by the disappearance of electronic coherence and a crossing of orbital polarization (enhanced in-plane d_x²-y² orbital occupancy). These changes weaken charge transfer at the interface and suppress the interfacial magnetic moment of Mn in CaMnO₃, indicating that the interfacial ferromagnetic state is directly governed by the electronic confinement of LaNiO₃. Density functional theory combined with dynamical mean-field theory successfully reproduces the insulating state and orbital reconstruction. This work confirms a direct and tunable coupling among electronic, orbital, and magnetic degrees of freedom in oxide heterostructures, providing a new pathway for designing correlated electron behavior in nanoscale spintronic materials. ...

Daily Overview: Today’s highlight focuses on an in-depth understanding of the electronic and orbital modulation mechanisms in nickelate-based perovskite heterojunctions. In [1], by employing in-situ synthesis, polarization-dependent angle-resolved photoemission spectroscopy, X-ray magnetic circular dichroism, and first-principles calculations, the study systematically reveals the dimensionality-driven metal-insulator transition and orbital polarization crossover in LaNiO₃/CaMnO₃ superlattices. It is found that in the ultrathin limit, LaNiO₃ exhibits an insulating state with enhanced in-plane dₓ²₋ᵧ² orbital occupancy. This electronic confinement effect directly weakens interfacial charge transfer and suppresses the ferromagnetic order of CaMnO₃, confirming the strong coupling tunability among electronic, orbital, and magnetic degrees of freedom, thereby providing a new pathway for designing nanoscale correlated electronic devices. arXiv submission processing window: 2026-04-30 01:47 to 2026-04-30 18:52 UTC. ...

Daily Overview: Today’s highlight work focuses on deepening the understanding of the electronic structure of mixed Ruddlesden-Popper nickelates. In [1], a study based on the DFT+DMFT method systematically reveals the significant electronic differences between alternating single-layer and double-layer Ni ions in La₅Ni₃O₁₁ (1212-LNO): the e_g states of the double-layer Ni exhibit strongly renormalized quasiparticle bands, while the single-layer Ni displays an orbital-selective Mott insulating state, where the 3z²-r² orbital opens a gap and the x²-y² orbital is metallic and incoherent. Magnetic correlation analysis suggests the possible formation of intertwined spin and charge density wave stripes in the double-layer NiO₆ slabs, along with an orbital-selective Mott insulator-metal transition under pressure. This work highlights the critical roles of interlayer confinement and orbital-dependent correlations in modulating the electronic behavior of nickelates, providing an important theoretical foundation for understanding the superconductivity and magnetism of such mixed RP phases. arXiv submission processing window: 2026-04-28 20:31 to 2026-04-29 18:08 UTC. ...

Daily Overview: Today’s highlights focus on the topochemical fluorination tuning of Ruddlesden-Popper nickelate single crystals and their electronic properties. In [2], researchers employed various fluorinating agents to topochemically fluorinate La₂NiO₄₊δ single crystals, inducing clear superstructures for the first time. Magnetization measurements confirmed that fluorination alters the antiferromagnetic order, offering a new pathway to modulate the magnetic and electronic properties of layered nickelates through post-growth methods. Additionally, the finding in [1] of direct competition between Bragg-Williams order and superconductivity extends the concept of competing orders beyond traditional degrees of freedom, closely relating to the competition between charge/spin order and superconductivity in nickel-based superconductors. The correlation-enhanced electron-phonon coupling mechanism revealed in [4] dominates superconducting pairing in hydrogenated FeSe (Tc > 40 K), providing a theoretical reference for understanding potentially similar strong-correlation pairing mechanisms in nickel-based superconductors. By distinguishing the distinct effects of electron doping and oxygen reduction on the pseudogap of cuprates, [5] emphasizes the crucial role of impurity oxygen—a perspective that offers insights for understanding the relationship between oxygen stoichiometry and superconductivity in nickelates. Other studies, such as [3,6,7,14,18], though not directly involving nickelates, investigate polar pairing, high-field magneto-optical imaging, multicomponent superconducting phase boundaries, non-local Cooper pairs, and two-dimensional magnonics, respectively, supplementing methodologies or physical perspectives for research on superconductivity and related quantum phenomena. arXiv submission processing window: 2026-04-27 21:02 to 2026-04-28 18:11 UTC. ...

Daily Overview: Dear readers, welcome to today’s quick overview of papers in the field of nickelate superconductors. Today, there are no papers directly studying nickelate superconductors, but several works explore common topics such as superconducting mechanisms, pairing symmetry, and phase transitions in strongly correlated electron systems, which are highly relevant to the core issues in the current nickelate superconductor field. Specifically, [2] band calculations for orthorhombic β-FeSe₁₋ₓ reveal the critical role of flat bands in maintaining superconductivity, and their pressure-dependent behavior can provide a reference for understanding the relationship between flat bands and superconductivity in nickelates; [5] half-integer flux trapping arising from frustration of the d-vector texture was discovered in a triplet superconducting Josephson junction network, which is instructive for exploring possible unconventional pairing states in nickel-based superconductors; [7] long-range electron-phonon coupling at the TMD/hBN interface was directly observed, and its forward scattering characteristics and quasiparticle weight renormalization effects can provide a new perspective for studying electron-phonon interactions in nickelate superconductors; [10] using neural network wave functions, novel superfluid states including a triangular lattice paired phase were discovered in two-dimensional spin-imbalanced Fermi gases, providing a computational framework for exploring similar nontrivial pairing orders in nickelate superconductors. These studies deepen the understanding of superconductivity and related strongly correlated phenomena from different perspectives, and deserve attention from scholars in this field. arXiv submission processing window: 2026-04-27 01:30 to 2026-04-27 19:48 UTC. ...

Daily Overview: In today’s paper digest, although no direct studies on nickel-based superconductivity are included, several works establish important connections with core issues in nickel-based superconductivity from perspectives such as unconventional superconducting mechanisms, material discovery methodologies, and spin dynamics. Highlights include: [1] reveals a change in vortex lattice symmetry and a linear temperature-dependent critical current density in the heavy-fermion superconductor CeCoIn5 using Campbell penetration depth measurements, providing new evidence for strongly correlated unconventional superconductivity; [4] observes that atomic-scale disorder in the maximally mixed-phase compound YBaCuFeO5 unexpectedly stabilizes coherent spin waves, overturning conventional understanding and offering reference value for possible disorder effects in nickelates; [2] introduces the ElementsClaw intelligent agent framework, which efficiently screens and experimentally validates four new superconductors, and its automated material discovery paradigm can be directly transferred to the search for candidate nickel-based superconducting phases. These outcomes collectively expand the physical understanding and research tools relevant to nickel-based superconductivity. arXiv submission processing window: 2026-04-25 23:34 to 2026-04-26 15:14 UTC. ...

Daily Overview: Today’s highlights focus on deepening the understanding of the electronic structure of hybrid Ruddlesden-Popper nickelates. However, this update does not include any papers directly studying nickelates. Nevertheless, a high-resolution ARPES study ([1]) on the intrinsic electronic structure of cuprate superconductors is highly relevant to the field of nickel-based superconductivity: for the first time, this work observes the coexistence of Fermi pockets and a superconducting gap as large as 33 meV at extremely low doping (0.007) in multilayer cuprates, revealing the synergy between strong electron pairing and antiferromagnetic order. This provides important insights for understanding similar doping-driven quantum phase transitions and pairing mechanisms in nickel-based superconductivity. Additionally, [2] discovers a vortex lattice without cores composed of half-quantum vortex bound states in the nematic superconductor LiFeAs, offering an experimental paradigm for exploring novel vortex states in multicomponent superconductors. [3] achieves a significant enhancement of the superconducting critical temperature (to approximately 1.8 K) in high-quality WTe₂ crystals and observes quantum oscillations for the first time, emphasizing the importance of disorder control for superconductivity enhancement. [5] visualizes the internal dynamics of vortex clusters in the weak type-II superconductor CaSb₂, revealing nonmonotonic vortex-vortex interactions. Although these works do not directly involve nickelates, the band structures, pairing mechanisms, vortex properties, and material synthesis strategies they reveal are instructive for addressing core challenges currently faced in nickel-based superconductivity, such as electronic phase diagrams, pairing symmetry, and sample quality optimization. arXiv submission processing window: 2026-04-25 03:09 to 2026-04-25 18:19 UTC. ...