Paper

Daily Overview: Today’s highlights focus on an in-depth understanding of the electronic structure of mixed Ruddlesden-Popper nickelates. In [1], first-principles simulations reveal a precise correspondence between the enhancement of electronic correlation strength driven by structural phase transitions and the superconducting dome in La₃Ni₂O₇, clarifying the key role of A-site cations in the pressure-tuned evolution of correlations. In [2], random phase approximation analysis from an itinerant electron perspective shows that the strength of Hund’s coupling determines the competition between superconducting pairing symmetry (s-wave or d-wave) and magnetic ordering wave vectors ((π/2, π/2) or (π, π)) in the bilayer nickelate system, providing crucial theoretical support for understanding the unconventional mechanism of nickelate superconductivity. arXiv submission processing window: 2026-02-25 00:00 to 2026-02-25 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-02-25

Daily Overview: The highlight of today’s work focuses on an in-depth understanding of the electronic structure of mixed Ruddlesden-Popper nickelates. In [1], DFT and RPA calculations revealed an s±-wave pairing mechanism in the bilayer subsystem of high-pressure La₅Ni₃O₁₁, where the monolayer subsystem is coupled to the bilayer via weak interlayer Josephson coupling, naturally explaining the dome-shaped Tc-pressure relationship and highlighting the distinct pressure response of mixed-phase compared to pure-phase nickelates. [2] proposes that applying a perpendicular electric field in La₃Ni₂O₇ single-double layer thin films can drive charge transfer, increasing the filling rate and thereby enhancing intralayer d-wave pairing, with theoretical predictions that Tc could exceed the liquid nitrogen temperature (~77 K), providing a new pathway for achieving high-temperature superconductivity at ambient pressure. [3] systematically constructs the superconducting phase diagram of multilayer square-planar nickelates Nd_{n+1}Ni_nO_{2n+2} (n = 4–8), achieving a maximum onset Tc of 12.9 K (n = 6), with magnetic fluctuations persisting in the superconducting region and the superconducting regime overlapping with that of infinite-layer nickelates, offering a template for atomic-precision layered design. [4] points out that in pressurized Ruddlesden-Popper nickelates, the incorrect formula used has systematically overestimated the superconducting volume fraction by approximately a factor of two (actual value only 51–59%), calling for recalculation using the correct equation, thus providing an important correction to the reliability of related experimental data. arXiv submission processing window: 2026-02-24 00:00 to 2026-02-24 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-02-24

Daily Overview: Today’s highlight focuses on the bosonic phase revealed by the superconductor-insulator transition in infinite-layer nickelate superconductors. By constructing a spatially periodic network structure to regulate the phase coherence of Cooper pairs, this study achieves a superconductor-insulator transition in samarium nickel oxide thin films and observes magnetoresistance oscillations with a period of h/2e, directly confirming the existence of 2e Cooper pairs in nickel oxides. Experiments indicate that the transition is primarily driven by enhanced superconducting fluctuations, and that Cooper pairs dominate charge transport throughout the transition process. The discovery of two anomalous metallic states—observed under finite and zero magnetic fields, respectively—can both be characterized by bosonic excitations, suggesting a key role of vortex dynamics in the ground state. This work establishes nickel oxides as a platform for studying the rich bosonic phases arising from the modulation of Cooper-pair phase coherence. arXiv submission processing window: 2026-02-23 00:00 to 2026-02-23 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-02-23

Daily Overview: Today’s highlights focus on deepening the understanding of the electronic structure of mixed Ruddlesden–Popper nickelates. In [1], a superconducting phase diagram was constructed by synthesizing multilayer planar tetragonal nickel oxide thin films (n = 3–8). Superconducting signatures were observed for n = 4 to 8, with the highest superconducting transition temperature of approximately 12.9 K at n = 6. The superconducting anisotropy reversal is attributed to the 4f electron moments at the Nd site, and the electronic structure approaches that of cuprates. Meanwhile, persistent magnetic fluctuations overlap with the superconducting region of infinite-layer nickelates, suggesting a common physical foundation. In [2], a reanalysis of the superconducting volume fraction in pressurized Ruddlesden–Popper nickel oxide (La₄Ni₃O₁₀) was conducted. It points out that the previously reported 81–86% value was overestimated by about a factor of two due to errors in treating the demagnetization factor in the formula derivation, with the actual value being 51–59%. It emphasizes that all related reports must be corrected based on standard magnetostatic formulas. These works provide critical insights into the phase diagram regularities and measurement reliability of nickel-based superconductivity. arXiv submission processing window: 2026-02-22 08:27 to 2026-02-22 17:34 UTC. ...

arXiv Daily: nickelate superconductors 2026-02-22

Daily Overview: Today’s highlights focus on advancing the understanding of the electronic structure of hybrid Ruddlesden-Popper nickelates. [1] By measuring the complete phase diagram of Nd({1-x})Sr(x)NiO(2) thin films via ellipsometry and employing a two-band Drude model, strong correlations and multiband superconducting characteristics were revealed: the spectral weights of the electron and hole bands undergo reconstruction with doping, and at optimal doping, both bands contribute to the superconducting condensation, directly confirming the multiband superconducting nature. [2] Using a neural quantum state method to simulate the mixed-dimensional (t\parallel)-(J\parallel)-(J\perp) model describing high-pressure bilayer nickelate La(_3)Ni(_2)O(_7), direct numerical evidence of ground-state superconductivity was obtained on an 8×8×2 lattice. A crossover from BEC-type pairing under strong interlayer coupling to BCS-type pairing under weak coupling was observed, along with a first-order phase transition from interlayer s-wave to intralayer d-wave pairing symmetry. These two works deepen the understanding of electronic correlations, multiband pairing, and pairing mechanisms in nickel-based superconductors from the perspectives of experimental spectroscopy and theoretical simulation, respectively. arXiv submission processing window: 2026-02-10 09:18 to 2026-02-10 18:55 UTC. ...

arXiv Daily: nickelate superconductors 2026-02-10