Paper

Daily Overview: Today’s highlights focus on deepening the understanding of the electronic structure of mixed Ruddlesden-Popper nickelates. In [1], the superconducting pairing in bilayer nickelate La₃Ni₂O₇ is revealed to have a hierarchical structure, with the primary pairing originating from the bonding-antibonding splitting of the Ni 3d({z^2}) orbitals, while orbital hybridization redistributes the superconducting correlations to the 3d({x^2-y^2}) channel. The resulting s± state is robust against changes in Fermi surface topology, unifying previously divergent theoretical perspectives. [2] unifies a series of experiments on the superconducting transition temperature of La₃Ni₂O₇ under oxygen stoichiometry, elemental substitution, pressure, and strain modulation, based on an effective d(_{x^2-y^2}) orbital bilayer t-J model. It is found that the Tc behavior resembles that of overdoped cuprates and exhibits particle-hole asymmetry, and it is proposed that electron doping can further enhance Tc. [3] focuses on the trilayer La₄Ni₃O₁₀, employing cluster exact diagonalization to reveal pressure-induced redistribution of oxygen hole states: under ambient pressure, excess holes are localized in the central NiO₂ layer and interlayer O p_z orbitals, while under high pressure they redistribute to the outer layers, emphasizing similarities with bilayer nickelates and proposing possible charge and spin ordered states. arXiv submission processing window: 2026-03-17 00:00 to 2026-03-17 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-03-17

Daily Overview: Today’s highlight work focuses on deepening the understanding of the electronic structure of hybrid Ruddlesden-Popper nickelates. In [1], using the newly discovered nickel-based superconductor La₃Ni₂O₇ as an example, the study reveals the “orbital dimerization” mechanism underlying its first-order structural phase transition. The authors find that standard DFT and LDA+DMFT methods fail to reproduce the abruptness of the phase transition due to neglecting key interatomic correlations. By constructing a many-body effective Hamiltonian involving low-energy active orbitals and performing exact diagonalization, they point out that when the Ni-O-Ni bond angle approaches linearity, the strong antiferromagnetic superexchange interaction between interlayer Ni orbitals forms spin-singlet bonding, leading to a sharp drop in total energy. This generates a new local energy minimum at a specific configuration, coexisting with the tilted configuration, perfectly explaining the first-order phase transition characteristics and the coexistence of high- and low-pressure structures observed in experiments. This mechanism not only alters the lattice bonding properties but also qualitatively changes the low-energy electronic structure (e.g., the emergence of superconductivity). The established DFT plus many-body correction computational framework provides key microscopic insights into understanding the structure-electronic property correlations in ionic materials containing open-shell d/f electrons. arXiv submission processing window: 2026-03-16 00:00 to 2026-03-16 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-03-16

Daily Overview: Today’s highlighted work focuses on a multi-perspective exploration of the superconductivity mechanism and phase diagram evolution in Ruddlesden-Popper phase bilayer nickelates. In [1], a review systematically summarizes the breakthrough progress in achieving ambient-pressure superconductivity in La₃Ni₂O₇ thin films, emphasizing the stabilization of the superconducting phase through epitaxial compressive strain and the controversial ARPES results regarding Fermi surface topology. It points out that weak-coupling theory predicts possible s± or d-wave pairing, but key issues remain unresolved. [2], from a theoretical perspective, proposes an orbital-space bilayer model (OSBM) and predicts that hole-doped reduced La₃Ni₂O₆ may be a new type of superconductor, with a pairing mechanism fundamentally different from that of La₃Ni₂O₇—driven by inter-orbital interactions in the incipient-band scenario, leading to s±-wave superconductivity, thereby opening a new theoretical direction for the nickelate superconductor family. [3] experimentally reveals the universal existence of a superconducting dome in compressively strained bilayer nickelate thin films. Through fine control of oxygen stoichiometry, it is found that strong scattering introduced by oxygen vacancies leads to a granular superconductor-insulator transition without changing the superconducting onset temperature, while interstitial oxygen mainly affects the carrier concentration. This phase diagram feature consistently appears across different rare-earth combinations and alkaline-earth-doped samples, providing key experimental evidence for understanding the relationship between electronic inhomogeneity and the emergence of superconductivity. arXiv submission processing window: 2026-03-13 00:00 to 2026-03-13 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-03-13

Daily Overview: Today’s highlights focus on the in-depth understanding of the electronic structure of mixed Ruddlesden-Popper nickelates. In [1], Zhou et al. achieved a superconducting onset temperature of approximately 63 K in (La,Pr)₃Ni₂O₂ thin films under ambient pressure via giant oxidative atomic layer epitaxy, and found that the superconducting enhancement is closely associated with strange metal behavior (α≈1), with significantly stronger interlayer coupling than that of bismuth-based cuprates. In [2], Wang et al.’s high-field transport study of La₂.₈₂Sr₀.₁₈Ni₂O₇ thin films revealed that the in-plane upper critical field is strongly suppressed by the Pauli paramagnetic limit (approximately 58 T), with an anisotropy ratio γ≈1.34, supporting a three-dimensional bulk superconductivity in this system and highlighting the critical role of spin paramagnetic effects in determining the high-field phase diagram. In [3], Sanchez-Manzano et al. characterized the superconducting dimensionality of infinite-layer Pr₀.₈Sr₀.₂NiO₂ thin films through vortex phase diagrams, discovering a quasi-two-dimensional vortex liquid-to-glass transition at low disorder, while enhanced disorder drives the system into a purely two-dimensional state, establishing disorder strength as a key tuning parameter. These three works collectively reveal the intrinsic relationships among dimensionality, interlayer coupling, and anomalous normal-state behavior in nickel-based superconductivity from the perspectives of superconducting enhancement mechanisms, paramagnetic pair-breaking limits, and vortex dimensionality tuning. arXiv submission processing window: 2026-03-12 00:00 to 2026-03-12 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-03-12

Daily Overview: Today’s highlights focus on deepening the understanding of the electronic structure of hybrid Ruddlesden–Popper nickelates. Two systematic muon spin rotation and resistivity studies, investigating the density wave orders in trilayer La₄Ni₃O₁₀ and bilayer La₃Ni₂O₇ respectively, employ pressure tuning and oxygen isotope substitution to reveal the intrinsic intertwining nature of spin density waves and charge density waves, as well as their distinct microscopic origins—the former primarily arising from electronic correlations, while the latter is significantly driven by electron–phonon coupling. The findings further suggest that suppressing the CDW order may be the key to achieving high-pressure superconductivity. These conclusions provide important constraints for understanding the pairing mechanism of high-pressure superconductivity in Ruddlesden–Popper nickelates. Additionally, a theoretical framework article starts from the ionically bonded O-/M bridging carrier pairing, unifying the pairing picture above room temperature in both cuprates and nickelates, and lists 32 pieces of experimental evidence to support its universality. Another study based on ARPES spectral scaling reveals that various strongly correlated materials, including La₃Ni₂O₇, exhibit universal spectral collapse in the marginal dynamics regime, indicating a universal dynamical origin for incoherent electronic states. Although these two works do not entirely focus on nickelates, they provide cross-support for the microscopic picture of their superconducting pairing mechanism and the unified understanding of their spectral features, respectively. arXiv submission processing window: 2026-03-11 00:00 to 2026-03-11 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-03-11