Paper

Daily Overview: Today’s highlighted work focuses on the microscopic theoretical elucidation of the magnetic ground state of the bilayer Ruddlesden–Popper nickelate La₃Ni₂O₇. Based on an orbital-selective Mott physics picture, the study describes the system as consisting of itinerant d_{x²−y²} quasiparticles coexisting with localized d_{z²} magnetic moments, and by integrating superexchange and RKKY interactions, reveals a magnetic frustration mechanism dominated by long-range coupling mediated by itinerant electrons. Theoretical calculations naturally yield a non-coplanar antiferromagnetic ground state consistent with neutron scattering experiments; the softening of the spin-wave spectrum at the ordering wave vector and the total bandwidth of about 80 meV are also consistent with resonant inelastic X-ray scattering data, indicating that orbital-selective correlations are the core factor determining the magnetism of bilayer nickelates and suggesting that low-energy magnetic fluctuations may provide the driving force for unconventional superconducting pairing. arXiv submission processing window: 2026-07-17 00:00 to 2026-07-17 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-07-17

Daily Overview: Today’s highlighted work centers on an in-depth understanding of the electronic structure of hybrid Ruddlesden–Popper nickelates. On the one hand, a theoretical study proposes a dual‑parameter control framework based on in‑plane d_(x²–y²) orbital filling and effective interlayer antiferromagnetic superexchange, providing a unified explanation for the systematic variation of the superconducting transition temperature in the bilayer nickelate La₃Ni₂O₇ under pressure, composition, and strain. It explicitly indicates that clean electron doping can enhance pairing strength, whereas oxygen vacancies suppress superconductivity by disrupting exchange pathways and inducing disorder effects. On the other hand, a high‑pressure single‑crystal structural investigation of the trilayer nickelate La₄Ni₃O₁₀ clarifies its direct transition path from the tetragonal to the monoclinic phase, reveals that pressure effectively stabilizes tetragonal symmetry, and detects faint structural distortions associated with density‑wave order. These findings provide key crystallographic evidence for the consensus that superconductivity emerges upon restoring the tetragonal phase under high pressure. Together, these two studies—from theory and experiment—deepen our understanding of the cooperative interplay among charge, spin, and lattice degrees of freedom in nickelates, and jointly point to a viable strategy for optimizing superconducting properties by controlling interlayer coupling and structural symmetry. arXiv submission processing window: 2026-07-16 00:00 to 2026-07-16 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-07-16

Daily Overview: Today’s highlight work focuses on the s+id mixed superconducting state induced by the synergistic effect of electronic correlations and electron-phonon coupling in infinite-layer nickelate superconductors. Investigations based on a combination of first-principles calculations and the fluctuation-exchange Migdal-Eliashberg theory reveal that spin fluctuations drive robust d-wave pairing in the Ni d_{x^2-y^2} orbital, while electron-phonon coupling induces an s-wave component in the interstitial orbitals. These two mechanisms synergistically form an s+id mixed superconducting state at a specific carrier density (e.g., n=0.9). The stability of this mixed state is highly sensitive to the local electron density. Local oxygen defects, by modulating the electron density, can create finite-sized domains with different pairing symmetries, thereby providing a microscopic explanation for the spatially inhomogeneous superconducting gap observed experimentally. These results profoundly underscore the crucial role of the synergy between correlation effects and electron-phonon coupling in determining the pairing symmetry of nickelate superconductors. arXiv submission processing window: 2026-07-15 00:00 to 2026-07-15 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-07-15

Daily Overview: Today’s highlight focuses on the multi-dimensional advancement of pairing symmetry, thin-film property control, and high-pressure spectroscopic characterization in nickelate superconductors. Theoretical studies reveal that in pressurized La₃Ni₂O₇, correlation-driven self-energy renormalization fundamentally reshapes the pairing hierarchy: upon incorporating the dynamical mean-field self-energy, the dominant pairing symmetry reverses from the B₂g dxy state given by conventional RPA to an A₁g s± state, indicating that correctly accounting for the correlation renormalization of quasiparticles is essential for predicting the pairing symmetry of bilayer nickelates. On the experimental side, Nd₁₋ₓEuₓNiO₂ infinite-layer films grown by pulsed laser deposition exhibit a broad superconducting dome in the range 0.2 ≤ x ≤ 0.5, with an optimal superconducting transition temperature as high as about 31 K at x = 0.3, outperforming results from other vacuum epitaxy techniques, and both underdoped and overdoped regions display magnetic-field-enhanced and reentrant superconductivity induced by the polarization of Eu²⁺ local magnetic moments. Furthermore, a newly developed high-pressure soft point-contact Andreev reflection spectroscopy technique has detected, for the first time in the bilayer nickelate La₂PrNi₂O₇, a sharp zero-bias conductance peak whose evolution with temperature, magnetic field, and pressure is characteristic of unconventional superconductivity and possible d-wave pairing symmetry, thus providing direct evidence from the microscopic spectroscopic perspective for elucidating the pairing mechanism in nickelate superconductors. arXiv submission processing window: 2026-07-14 00:00 to 2026-07-14 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-07-14

Daily Overview: Today’s highlighted work focuses on the elucidation of the electronic structure of low-n-layer tetragonal nickelates and the theoretical exploration of new electron doping strategies. One study employs the DFT+DMFT method to reveal layer-resolved correlation effects: in the undoped system, the electronic correlation of Ni-d orbitals increases with the number of layers, and the inner NiO₂ planes are generally more strongly correlated than the outer ones. Through an electron compensation strategy involving Cl substitution in the spacer layer, the nominal Ni valence is tuned to a level comparable to that of optimal superconducting systems, and it is predicted that these systems can enter a strongly correlated metallic regime, providing a feasible pathway to transform low-layer nickelates into potential superconducting candidates. Another work proposes achieving disorder-free electron doping in nickelates via a heterostructure approach: by inserting a wide-bandgap insulating LaXO₃ layer, La₂NiO₄ accepts extra electrons supplied by (LaO)⁺ layers. Many-body theoretical calculations predict that the superconducting transition temperature can exceed 50 K and even reach as high as 127 K. This method is also applicable to systems such as La₃Ni₂O₇, opening a general scheme for the comprehensive exploration of the electron doping phase diagram of nickelates. arXiv submission processing window: 2026-07-10 00:00 to 2026-07-10 00:00 UTC. ...

arXiv Daily: nickelate superconductors 2026-07-10