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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: This post sorts papers by relevance to nickelate superconductors. Summaries are AI-generated and may contain errors. 1. Dimensionality-Driven Electronic and Orbital Transitions Mediating Interfacial Magnetism in LaNiO3/CaMnO3 Observed In Situ Relevance Score: 4.9640 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 Link: http://arxiv.org/abs/2604.28054v1 Summary: Emergent magnetic states at oxide interfaces arise from the interplay of charge transfer, orbital reconstruction, and dimensional confinement, offering a route to engineered correlated-electron behavior in nanoscale spintronic materials. Here, we combine in situ synthesis, polarization-dependent angle-resolved photoelectron spectroscopy, X-ray magnetic circular dichroism, and first-principles electronic-structure calculations to investigate LaNiO3/CaMnO3 superlattices. We show that reducing the LaNiO3 thickness drives a metal-insulator transition accompanied by loss of electronic coherence and an orbital-polarization crossover in the ultrathin limit. These changes weaken charge transfer across the interface and suppress the interfacial Mn magnetic moment in CaMnO3, revealing that the emergent ferromagnetic state is directly governed by electronic confinement in LaNiO3. The insulating state and orbital reconstruction are reproduced by density functional theory combined with dynamical mean-field theory. Together, these results establish a direct and tunable coupling among electronic, orbital, and magnetic degrees of freedom in oxide heterostructures. ...

Daily Overview: Dear readers, welcome to today’s daily overview of the nickelate superconductor field. The highlight of today focuses on a deeper understanding of the electronic structure of hybrid Ruddlesden-Popper nickelates. In [1], a theoretical study using the DFT+DMOT method reveals that the monolayer-bilayer alternating structure of La₅Ni₃O₁₁ exhibits distinctly different electronic behaviors under ambient pressure. Specifically, the monolayer Ni ions display an orbital-selective Mott insulating state, while the bilayer Ni ions exhibit strongly correlated quasiparticle behavior, with magnetic correlations predominantly governed by the bilayer. This work unveils the critical role of confinement effects and orbital-dependent correlations in determining the physical properties of nickel-based superconductors. Additionally, several other studies in today’s overview are worth noting: - [2] A high-pressure study of the cluster Mott insulator GaNb₄Se₈ demonstrates the evolution from “wavefunction collapse” to superconductivity, providing an ideal platform for understanding pressure-induced Mott transitions in correlated systems. - [3] Proposes a scheme to achieve high-temperature superconductivity on the surface of Weyl semimetals by engineering Van Hove singularities. This interface-enhanced superconductivity mechanism parallels the approach of exploring superconductivity in nickelate thin-film interfaces and is highly inspiring. - [8] Realizes a programmable superconducting diode effect in the nematic superconductor FeSe, demonstrating a method to manipulate the superconducting state by controlling nematic domains. This offers new tuning dimensions and technical paradigms for the study of nickel-based superconductors that exhibit similar electronic correlations and nematic order. The above direct research on nickelates, along with physically related work, constitutes the core content of today’s overview. ...

Daily Overview: Today’s highlight work focuses on the controllable experimental realization of multi-orbital models in strongly correlated electron systems, which is highly relevant to the current pursuit of understanding complex electronic structures in the field of nickel-based superconductivity. In [1], the researchers propose a novel architecture based on ultracold fermions and optical superlattices, successfully realizing the three-band Emery model—a core theoretical framework for describing the low-energy physics of cuprate and nickel-based superconductors. By precisely tuning orbital-dependent interactions and charge transfer energies, and combining quantum walk experiments with quantum Monte Carlo simulations, this work observes, for the first time in an undoped system, a finite-temperature metal-insulator crossover and the consequent emergence of antiferromagnetic correlations, which bears a profound analogy to the electronic correlation behavior in nickel-based superconducting parent compounds. Furthermore, the Hamiltonian learning protocol developed in this study can invert experimental data to extract an effective single-band Hubbard model, providing a novel methodology for resolving effective low-energy models in future multi-orbital nickelate systems. Although the remaining papers do not directly target nickelates, their investigations into strong-coupling superconductivity theory, electron-phonon coupling dynamics, and interface defect engineering also offer valuable references for frontier issues such as the ambient-pressure pairing mechanism, excitonic effects, and interface engineering in nickel-based superconductivity. arXiv submission processing window: 2026-04-23 20:33 to 2026-04-24 18:58 UTC. ...

Daily Overview: Today’s highlights focus on an in-depth understanding of the electronic structure of mixed Ruddlesden-Popper nickelates. In [1], X-ray absorption spectroscopy and resonant inelastic X-ray scattering studies on (La,Pr)₃Ni₂O₇₋δ thin films reveal that both strain and oxygen content modulation lead to the delocalization of the oxygen 2p₂ orbital and the nickel 3d₂² orbital, while long-range spin density wave order is significantly suppressed, and short-range magnons remain robust, indicating that orbital delocalization and short-range magnetic fluctuations are prerequisites for superconductivity. [2] provides a theoretical analysis of the 1313-phase La₃Ni₂O₇, pointing out that its superconductivity primarily originates from a three-layer subsystem with s^{±}-wave pairing symmetry, but the single-layer subsystem, acting as a weakly connected layer forming S-N-S Josephson junctions, suppresses the global transition temperature. This work thus deduces that the 2222-phase, rather than the 1313-phase, is the true host of high-temperature superconductivity in the RP-phase La₃Ni₂O₇ family. These two studies deepen the understanding of the superconducting mechanism in nickelates from experimental and theoretical perspectives, respectively. arXiv submission processing window: 2026-04-22 20:37 to 2026-04-23 18:00 UTC. ...

Daily Overview: The highlight of today’s work focuses on deepening the understanding of the electronic structure of mixed Ruddlesden-Popper nickelates. In [1], a review systematically elaborates on the strong-coupling Hund’s rule-assisted pairing mechanism in bilayer La₃Ni₂O₇, pointing out that the strong interlayer antiferromagnetic exchange mediated by the inner apical oxygen of the 3d_z² orbital cooperates with the itinerant nature of the 3d_x²-y² orbital, forming effective interlayer pairing via Hund’s coupling, which drives extended s-wave superconductivity. Meanwhile, localized ladder singlets give rise to a pseudogap phase, providing a unified theoretical framework for high-temperature superconductivity in this system. Additionally, although several other papers do not directly investigate nickelates, the physical mechanisms they explore are highly relevant to the core issues currently addressed in nickel-based superconductivity. For example, [3] discovers a parity-breaking charge density wave and pairing density wave in kagome metals, offering new perspectives for understanding quantum geometry and pairing symmetry in unconventional superconductors. In [12], perfect spin non-reciprocity is achieved in superconducting alternating magnetic heterostructures, with its momentum-selective filtering strategy inspiring spin transport manipulation in nickel-based heterojunctions. Meanwhile, [7] manipulates van Hove singularities in antimony telluride superlattices via layer-number control, providing a tunable pathway for driving correlated quantum states through dimensionality engineering in nickelates. These advancements collectively deepen the understanding of electron correlations, symmetry, and pairing mechanisms in strongly correlated superconducting systems. arXiv submission processing window: 2026-04-22 00:02 to 2026-04-22 19:31 UTC. ...

Daily Overview: Greetings readers, welcome to today’s overview of papers in the nickel-based superconductivity field. Although no works directly targeting nickelates as the research subject are included today, multiple papers focus on physical mechanisms closely related to the core issues of nickel-based superconductivity. Among them, [1] decomposes the pseudogap in cuprates via nuclear magnetic resonance shift, proposing three condensation rules for spin-singlet pairing, thereby providing a unified framework for understanding the electronic phase diagram of layered oxide superconductors. [13], based on real-space Ginzburg-Landau analysis, explores the inversion symmetry breaking and chirality induced by four-layer charge density waves in the Kagome superconductor CsV₃Sb₅, with conclusions that are relevant to similar possible CDW order in nickelates. [20] introduces hidden hyperuniform disorder into the Hubbard model, revealing the high sensitivity of electronic states and magnetic phase transitions in correlated systems to ordered microstructures, offering new insights into the regulation of disorder effects in nickelates. arXiv submission processing window: 2026-04-20 20:00 to 2026-04-21 18:14 UTC. ...

Daily Overview: Today’s highlights focus on deepening the understanding of the electronic structure of mixed Ruddlesden-Popper nickelates. In [1], a review systematically summarizes experimental and theoretical progress on RP-phase nickel oxide superconductors, emphasizing that ultra-thin La₃Ni₂O₇ films grown on compressively strained substrates achieve ambient-pressure superconductivity, enabling experimental techniques such as angle-resolved photoemission spectroscopy. Theoretically, the Ni e_g and a_{1g} orbitals and the interlayer dimer picture are highlighted as key factors. In [3], density matrix renormalization group simulations of a three-leg t-J ladder with strong inter-chain coupling reveal that pair correlation functions exhibit power-law decay near 1/3 hole doping, forming asymmetric pairing compared to electron doping, providing numerical evidence for understanding the electronic properties of trilayer nickelate superconductors. These works collectively advance the understanding of the microscopic mechanism of nickel-based superconductivity. arXiv submission processing window: 2026-04-19 20:01 to 2026-04-20 19:34 UTC. ...

Daily Overview: Today’s highlights focus on the pairing mechanism of the bilayer nickelate La₃Ni₂O₇ high-temperature superconductor, revealing that a unified framework based on the “gene principle” and the “cooperative Fermi surface rule” can be naturally extended to this bilayer multi-orbital system. Two dominant antiferromagnetic superexchange channels cooperatively generate a stable s± superconducting state, offering new perspectives for understanding the unique electronic environment of nickel-based superconductivity. Additionally, although not directly targeting nickelates, today’s list includes studies on the G-type antiferromagnetic order and hidden altermagnetism in Rb₁₋ₓV₂Te₂O, as well as the microscopic detection of hidden magnetic entropy in the orbital glass state of Ba₂NaOsO₆. The physical mechanisms explored in these studies—such as spin-orbit coupling, hidden order, and d-wave spin splitting—are closely related to the core issues currently addressed in the field of nickel-based superconductivity, including pairing symmetry, spin fluctuations, and orbital effects, warranting cross-disciplinary attention. arXiv submission processing window: 2026-04-19 00:56 to 2026-04-19 18:01 UTC. ...