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Daily Overview: Dear readers, today’s rapid overview of the nickel-based superconductivity field presents a core research advance: using ultralow-temperature scanning tunneling microscopy/spectroscopy, researchers have for the first time observed an energy-symmetric flat-bottomed U-shaped superconducting gap in (La,Pr)₃Ni₂O₇ thin films, confirming its nodeless gap nature. This gap exhibits zero density of states at extremely low temperatures, evolves into a V-shape as temperature increases, and is suppressed by magnetic fields, behaving consistently with conventional superconducting gaps. This discovery reveals a new mechanism for high-temperature superconductivity in double-layer nickelates, offering insightful clues for achieving even higher-temperature superconductivity under ambient or zero pressure. Apart from this closely related paper, the remaining articles do not involve nickel-based superconductivity. ...

Daily Overview: Today’s research in the field of nickelate superconductivity is characterized by a robust trend of experimental deepening and theoretical unification. On the experimental front, a study combining atomic-resolution scanning tunneling microscopy with spectroscopy has, for the first time, directly observed a nodeless U-shaped superconducting gap in (La,Pr)₃Ni₂O₇ superconducting thin films. It also reveals that precise control of oxygen content is an essential prerequisite for obtaining intrinsic spectra, providing key evidence for understanding the pairing symmetry of superconductivity. At the theoretical level, an important paper proposes a unified framework of “shear-stress-constrained superconductivity,” insightfully pointing out that non-hydrostatic pressure or epitaxial strain themselves are not the direct cause of superconductivity; rather, the key lies in the local Ni-O framework constraint deformation achieved through shear stress. This scenario offers a cross-scale unified quantitative perspective for understanding the fragility, heterogeneity, and reproducibility challenges of superconducting behavior in both high-pressure bulk and thin-film systems. Additionally, this week’s submissions also include several studies on strongly correlated electron systems closely related to superconductivity, such as a dynamical scaling analysis of the pseudogap-to-Fermi-liquid quantum critical point in the two-dimensional Hubbard model, and an ultrafast spectroscopy study of the rapid decoupling between quasiparticles and spin fluctuations in superconducting cuprates. These works, in mutual reflection with core issues in the nickelate field, collectively advance the understanding of unconventional superconductivity and strongly correlated electronic states. ...

Daily Overview: Today, there are no directly related new paper preprints on the field of nickelate superconductors. However, several works in this issue focus on superconductivity, strongly correlated electron systems, and unconventional pairing mechanisms, which are highly relevant to the core scientific questions of nickelate superconductors. For example, [1] presents direct evidence of quantum critical spin fluctuations in the strange metal phase of cuprates via nuclear magnetic resonance, and its spatial inhomogeneity and electronic phase separation characteristics offer valuable insights for understanding analogous phenomena in nickelates. [3] discovers a strongly correlation-driven Nagaoka supermetal state in the triangular-lattice Hubbard model; its sublinear resistivity behavior and band renormalization mechanism provide a new perspective for exploring non-Fermi liquid behavior in nickelates. [8] systematically analyzes superconducting pairing symmetries in multiorbital systems using the exactly solvable Hatsugai-Kohmoto model, offering a theoretical framework for understanding orbital-selective pairing in nickelates. [11] and [15] investigate symmetry-driven topological superconducting states in altermagnets and spin-filtering and nonreciprocal transport in altermagnet/Ising superconductor junctions, respectively; these synergistic effects of spin-orbit coupling and superconductivity are instructive for designing nickelate-based heterostructures. Although these studies do not directly address nickelates, the strongly correlated physics, pairing symmetries, and interface effects they reveal are expected to provide important references for exploring the mechanism and functional applications of nickelate superconductors. ...

Daily Overview: Today’s rapid overview of the nickelate superconductor field focuses on an important review work. A collaborative team from Nankai University and Zhejiang University has systematically summarized the experimental progress of superconducting bilayer nickelate thin films (RA₃Ni₂O₇) under ambient pressure. The review points out that La₃Ni₂O₇ and (La,Pr)₃Ni₂O₇ thin films grown on substrates such as SrLaAlO₄ via epitaxial strain have achieved superconducting onset temperatures exceeding 40 K, successfully reproducing the key structural features of high-pressure bulk materials under ambient conditions. However, the maximum superconducting transition temperature in current thin films remains lower than that of high-pressure bulk materials, indicating room for optimization. The article discusses synthesis methods, oxygen stoichiometry control, substrate-induced strain, normal-state transport behavior, and doping phase diagrams, while identifying several unresolved key issues, including the reproducibility of phase-pure ultrathin films, the microscopic origin of the two-step superconducting transition, the roles of oxygen defects and substrate doping, the Fermi surface crossing position of the Ni 3d(_{z^2}) (\gamma) band, and the pairing symmetry. This work provides a controllable platform for understanding the microscopic mechanism of nickel-based superconductivity and clarifies the direction for future establishment of quantitative relationships among crystal structure, orbital reconstruction, and superconductivity. Only this one paper is featured today, but its content encompasses the latest experimental landscape and core challenges in the field. ...

Daily Overview: Dear readers! Today marks an important theoretical advancement in the field of nickel-based superconductivity. Paper [1] systematically reveals the orbital-selective Fermi surface reconstruction driven by electronic correlations in the bilayer nickel oxide La₃Ni₂O₇, using cluster perturbation theory and density matrix renormalization group methods: under weak coupling, superconductivity is dominated by interlayer spin-singlet pairing from the d_{z²} orbital, while under strong coupling it transitions to dominance by the d_{x²-y²} orbital, yet always maintaining an s± pairing structure. This discovery elucidates the mechanism connecting the disappearance of the γ pocket with superconductivity, providing a key microscopic picture for understanding the origin of high-temperature superconductivity in this system. > Additionally, Paper [3] focuses on rare-earth nickelates RNiO₃, proposing a multi-orbital model that uniformly describes charge, spin, orbital, and lattice degrees of freedom, predicting a nonmagnetic charge-orbital ordered insulating phase induced by the Jahn-Teller effect. This provides a theoretical basis for explaining the anomalous experimental phenomenon where the metal-insulator transition temperature is higher than the magnetic ordering temperature in small-bandwidth systems. > This issue also includes other cutting-edge works in superconductivity and condensed matter physics, such as the transverse magnetic response of orbital-polarized Cooper pairs in elemental superconductors, the origin of apparent double Tc in anisotropic phase models, Ginzburg-Landau theory for confined superconducting thin films, and long-range magnetic coupling mediated by superconductivity, for your reference. ...

Daily Overview: Although today’s daily paper overview does not directly include works related to nickelate superconductors, it covers several highlights closely tied to unconventional superconductivity, topological superconductivity, and strongly correlated electron systems, offering multidimensional perspectives for understanding superconducting pairing mechanisms and quantum state manipulation. Key highlights include: 《(BaS)₁/₃TaS₂》 achieves bulk two-dimensional Ising superconductivity with both high transition temperature and large interlayer spacing, breaking traditional trade-offs through a chain-intercalation strategy; 《d-wave altermagnets》 reveals that d-wave altermagnets can stabilize finite-temperature pair density wave phases without an external magnetic field; 《cuprate superconductivity》 uses first-principles three-band modeling to confirm the indispensability of long-range hopping for the superconducting dome and pairing symmetry in cuprates; 《twisted bilayer cuprates》 predicts topological superconducting states with Chern numbers up to ±8 under electron doping in a weakly interacting Hubbard model; 《Majorana bound states》 provides an analytical framework for Majorana modes hosted by skyrmion-vortex pairs in chiral ferromagnet-superconductor heterostructures. Additionally, the discovery of the three-dimensional bipartite quantum spin liquid candidate material KBa₃Ca₄Cu₃V₇O₂₈, and the successful decoupling of RuO₂ surface electronic states from bulk states, provide important experimental foundations for studying novel quantum states in correlated electron systems. ...

Daily Overview: Today’s Quick Overview of the Ni-Based Superconductor Field > Among today’s submissions, no research papers directly targeting nickel-based superconductors were found. However, several works have made important progress in closely related directions such as superconducting mechanisms, strongly correlated electron systems, and topological superconductivity, offering potential insights for nickel-based superconductor research: > 1. Cuprate Superconductivity Theory: A work systematically studying the three-band Emery model via the dynamical vertex approximation (DA) is noteworthy. The study points out that traditional simplified models are insufficient for quantitatively describing the cuprate superconducting phase diagram; instead, the full set of long-range hopping parameters derived from first principles must be included to obtain a superconducting dome (doping range 7–22%) and d-wave order parameter consistent with experiments. Given the electronic structure similarities between nickel-based superconductors and cuprates, this methodology has direct reference value for theoretical modeling of nickel-based superconductors. > 2. Topological Superconductivity in Twisted Bilayer Hubbard Model: A study using the variational cluster approximation investigates topological superconductivity in twisted cuprate bilayers. It reveals that in the weak-interaction regime below the Mott transition, the electron-doped side can realize nontrivial topological superconducting states with Chern numbers up to ±8, while the hole-doped side remains topologically trivial. This microscopic mechanism provides a theoretical framework for exploring possible topological phases in nickel-based superconductors. > 3. Pair-Density Wave in Altermagnets: A non-perturbative Monte Carlo study reveals that d-wave altermagnets can stabilize finite-momentum superconductivity (pair-density wave) without requiring an external magnetic field. This originates from the momentum-dependent spin splitting, which effectively enhances pairing at finite center-of-mass momentum while suppressing the uniform superconducting channel. This mechanism offers a new perspective for understanding possible incommensurate superconducting orders in nickel-based superconductors. > 4. Theory of Majorana Bound States: An analytical theoretical work on chiral ferromagnet–superconductor heterostructures clarifies the crucial role of spin-orbit coupling for the existence of Majorana zero modes and provides the threshold condition for the spin-orbit coupling strength. These results have theoretical guiding significance for designing topological quantum computing platforms based on nickel-based superconductors. > Summary: Although no studies directly targeting nickel-based superconductors were submitted today, theoretical advances in directions such as multi-orbital models for cuprates, topological superconductivity in twisted bilayers, and pair-density waves in altermagnets provide important inspiration for refined modeling, topological state exploration, and understanding of unconventional superconducting mechanisms in nickel-based superconductor systems, meriting the attention of researchers in the field. 1. Breaking the Trade-off: Bulk 2D Ising Superconductivity with High Tc and Giant Interlayer Spacing via a Unique Chain Intercalation in (BaS)1/3TaS2 Relevance Score: 4.3582 Authors: Ziyi Zhu, Leiming Chen, Xiangqi Liu, Haonan Wang, Chen Xu, Ze Yan, Zhengyang Li, Wei Xia, Jiawei Luo, Na Yu, Xia Wang, Ke Qu, Zhenzhong Yang, Yanfeng Guo Affiliations: East China Normal University, ShanghaiTech University, Zhengzhou University of Aeronautics Link: http://arxiv.org/abs/2605.07336v1 Summary: This paper reports the synthesis of a new polymorph, (BaS)₁/₃TaS₂, via a unique chain-like intercalation strategy, which successfully overcomes the long-standing trade-off between high superconducting transition temperature (Tc) and increased interlayer spacing/enhanced two-dimensionality in conventional intercalation systems. In this structure, Ba-S-S-Ba chains are inserted between TaS₂ bilayers, forming locally decoupled two-dimensional superconducting layers with an interlayer spacing of 12.75 Å, more than three times that of pristine 2H-TaS₂. This structural configuration breaks the bulk c-axis mirror symmetry, significantly suppresses interlayer electronic coupling, and renders local inversion symmetry breaking within individual TaS₂ layers dominant, thereby avoiding the compensation of the Ising spin–orbit field in the centrosymmetric bulk and realizing robust bulk two-dimensional Ising superconductivity. Comprehensive transport, magnetic, and thermodynamic measurements confirm that (BaS)₁/₃TaS₂ exhibits an enhanced Tc, an in-plane upper critical field far exceeding the Pauli limit, and pronounced superconducting anisotropy, demonstrating the successful coexistence of high Tc with large interlayer spacing/high two-dimensionality. This work establishes a generic intercalation framework for designing bulk two-dimensional Ising superconductors, offering a new route to reconcile competing demands in materials and expanding the scope of Ising superconductivity research. ...

Daily Overview: No relevant papers have been published in the field of nickel-based superconductivity today. 1. Pair-Breaking and Dimensionality in Spin-Orbit Coupled Superconductors Relevance Score: 4.5787 Authors: Reiley Dorrian, Mizuki Ohno, Elena Williams, Adrian Llanos, Joseph Falson Link: http://arxiv.org/abs/2605.06514v1 Summary: This paper employs the multi-mechanism Kharitonov-Feigel’man (KF) framework to analyze the thickness-dependent superconductivity in spin-orbit-coupled superconducting thin films of LaBi₂, and systematically compares it with the conventional Klemm-Luther-Beasley (KLB) model. A series of high-quality single-crystal films ranging from the “bulk” to the ultrathin limit (2.1 nm) were prepared by molecular beam epitaxy, and the temperature-dependent upper critical fields were measured under parallel magnetic fields. In contrast to the KLB model, which only considers paramagnetic pair-breaking, the KF framework simultaneously incorporates three mechanisms: orbital pair-breaking, paramagnetic effects, and magnetic scattering (spin-exchange scattering). An anomalous enhancement of the critical field was observed in the ultrathin limit (2.1 nm), attributed to the suppression of magnetic fluctuations by the magnetic field, which effectively reduces the spin-exchange scattering rate. Through fitting with the KF model, the contributions of each scattering channel were successfully isolated: the magnetic scattering time is on the order of 10⁻¹²–10⁻¹¹ seconds, while the KLB model, due to its neglect of orbital pair-breaking, severely overestimates the spin-orbit scattering time (by up to four orders of magnitude) at finite thickness and is meaningful only in the zero-thickness limit. The study also reveals differences among three distinct definitions of the zero-field critical temperature (experimental value, KLB extrapolated value, and KF value without magnetic impurities), and emphasizes that the determination of the Pauli limit should be extrapolated to the strictly two-dimensional limit. The results indicate that the KLB model, by ignoring magnetic disorder and orbital effects, introduces systematic biases in the interpretation of fundamental superconducting parameters (such as critical temperature and Pauli limit), whereas the KF framework provides a more accurate deconstruction of pair-breaking mechanisms in two-dimensional superconductors, offering new insights into the relationship between scattering times and superconductivity. ...

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. ...