Announcement date: 2026-11-11; usually generated on 2026-11-12 Beijing time No newly matched papers yesterday This does not mean arXiv had no papers yesterday. It means the papers announced yesterday did not produce an accepted match for this site's nickelate superconductors scope after relevance ranking and domain review. ...
arXiv Daily: no new papers for 2026-11-11
Daily Overview: Today’s highlighted work focuses on deeper understanding of the electronic structure of mixed Ruddlesden–Popper nickelates. Experimentally, [1] grew four-layer Ruddlesden–Popper nickelate La5Ni4O13 bulk single crystals by a high-pressure high-temperature method and reproduced the synthesis of La6Ni5O16, then topochemically reduced La5Ni4O13 single crystals with CaH2 to obtain the square-planar phase La5Ni4O10; this reduced phase exhibits bulk superconductivity at ambient pressure, with Tc^onset ≈18 K and a zero-field-cooled shielding fraction exceeding 60%, a specific-heat jump supports a bulk pairing transition, and in all crystals superconductivity coexists with a density-wave or metal–insulator transition; the upper-critical-field anisotropy γ≈2.4 remains finite as T→Tc, indicating three-dimensional superconducting characteristics and significant coupling between four-layer blocks, on which basis the authors propose that R_{n+1}Ni_nO_{2n+2} square-planar nickelates can enter the superconducting region solely by tuning the Ni valence through the layer number, without chemical substitution, applied pressure, or epitaxial constraint. Theoretically, [2] addresses the contradiction between the nodeless bulk gap and d-wave-like point-contact transport in La3Ni2O7 by assuming that strong interlayer antiferromagnetic coupling drives interlayer pairing as the dominant pairing channel and introducing interlayer and intralayer pairing amplitudes in a two-orbital tight-binding model to reproduce the ARPES/STM multiple-gap structure; the analysis shows that when the point contact couples unequally to the two layers, a contact potential odd under layer-exchange mirror symmetry can act as an effective Zeeman field for layer pseudospin, bind in-gap Andreev states in the barrier region, and in the mirror eigenbasis mix mirror sectors with opposite pairing signs, opening Andreev channels with reversed pairing sign; simulations of the top-layer barrier in La3Ni2O7 reproduce the orientation-dependent zero-bias conductance peaks and side peaks usually regarded as d-wave fingerprints, showing that a nodeless interlayer pairing state can mimic d-wave Andreev signals. Another theoretical work [3] gives spin-fluctuation-induced dominant d_{x^2-y^2}-wave pairing within a five-layer Hubbard model and RPA framework for bulk La6Ni5O12 and examines two phenomenological electron-phonon couplings inspired by the oxygen breathing mode: when present alone, both tend to favor s-wave, and attractive scattering between regions where the spin-fluctuation-induced gap has opposite signs suppresses d-wave pairing; after electron charge screening is included, this suppression is significantly weakened, the boundary between s-wave and d-wave pairing strength shifts toward the d-wave-favorable side, and momentum-resolved projection further locates where the unfavorable scattering processes are weakened, with d-wave pairing remaining dominant under representative electron interactions, thus emphasizing the competing roles of the momentum structure of electron-phonon coupling and charge screening in spin-fluctuation d-wave pairing. arXiv submission processing window: 2026-11-10 00:00 to 2026-11-10 00:00 UTC. ...
arXiv Daily: nickelate superconductors 2026-11-10
Daily Overview: The highlighted work today focuses on a theoretical study of interlayer superconductivity in a La3Ni2O7-inspired bilayer t-J-J⊥ ladder rather than on experimental observations; in this model, t is the in-plane electron hopping, J is the in-plane spin exchange, and J⊥ is the interlayer spin exchange. The authors use the density matrix renormalization group method, tune J⊥ over a large doping range δ=1/8–1/2, and construct a quantum phase diagram using spin-singlet pairing correlations as the main criterion. The theoretical results indicate that sufficiently large J⊥ can drive interlayer superconductivity in both Luther-Emery-liquid and Luttinger-liquid parent states: when two Luther-Emery liquids are coupled, in-plane superconductivity can transform into interlayer superconductivity either through an intermediate charge density wave (CDW) phase over a finite doping interval or directly, with this CDW phase evolving from the CDW state of the two-leg ladder at δ=1/4; when two Luttinger liquids are coupled, large J⊥ drives the system into interlayer superconductivity, whereas at intermediate J⊥ the in-plane Luttinger-liquid features remain stable, and the interlayer superconductivity exhibits enhanced quasi-long-range order with a power-law exponent Kzz_SC~1. Results for the three-layer ladder further indicate that strong J⊥ can stabilize interlayer superconductivity over a wider doping range, providing numerical evidence for understanding interlayer pairing in bilayer cuprates and nickelates. arXiv submission processing window: 2026-11-06 00:00 to 2026-11-06 00:00 UTC. ...
arXiv Daily: nickelate superconductors 2026-11-06
Daily Overview: Today’s highlighted work focuses on a deeper understanding of the electronic structure of mixed-type Ruddlesden-Popper nickelates. On the theoretical side, [1] combines variational Monte Carlo calculations within an effective five-layer Hubbard model and finds that the spin-singlet d_{x^2-y^2}-wave state of La6Ni5O12 is energetically favored while extended s-wave pairing is strongly suppressed; based on the optimized superconducting state, [1] predicts signatures of a clean nodal superconductor, including a V-shaped tunneling density of states, linear depletion of the low-temperature superfluid density, a decrease in the Knight shift below Tc, and 1/(T1T)∝T^2. Within the same framework, LaNiO2 shows a robust d-wave tendency, and La4Ni3O8 lies close to the boundary between d-wave superconducting and non-superconducting states; on this basis, [1] proposes that a common d_{x^2-y^2}-wave pairing tendency may exist in the reduced RP nickelate family but emphasizes that this remains a theoretical prediction rather than an experimental establishment. On the experimental side, [2] uses 139La NQR spectra of La3Ni2O7.0 at ambient pressure combined with DFT+U calculations, observes two La(2)a/La(2)b sites with near-1:1 occupancy, points out that the two intrinsic inequivalent La(2) sites and two inequivalent Ni sites in the low-symmetry Am2m (No.38) structure naturally explain this phenomenon, and rules out defect models attributing the signal to stacking faults, impurity phases, or oxygen vacancies; based on the Am2m framework, [2] identifies the commensurate SDW state as “large-small spin stripe” order, in which different internal fields are associated with the small magnetic moment at Nia and the larger magnetic moment at Nib, respectively, and the small-spin Ni site has higher electron occupancy but a smaller magnetic moment, inconsistent with the local-moment picture, indicating that the ambient-pressure SDW order is driven by Fermi-surface nesting and is itinerant in nature. On the model side, [3] performs finite-temperature determinant quantum Monte Carlo simulations of a single-orbital bilayer Hubbard model under conditions of strong interlayer coupling and comparable intralayer and interlayer antiferromagnetic correlation strengths, showing that spin stripes form spontaneously with increasing hole doping and that the dominant pairing symmetry crosses from d-wave to s±-wave; this crossover tracks changes in the relative strengths of the two types of spin correlations, and the odd-channel dynamic spin structure factor further exhibits momentum-dependent reorganization of magnetic excitations. On this basis, [3] considers the spin-fluctuation structure to be a key link connecting spin stripes and pairing competition, providing a minimal-model perspective for understanding La3Ni2O7, although this result is a model-calculation prediction rather than an established experimental mechanism. arXiv submission processing window: 2026-11-05 00:00 to 2026-11-05 00:00 UTC. ...
arXiv Daily: nickelate superconductors 2026-11-05
Daily Overview: The highlighted work today focuses on an ambient-pressure Raman scattering study of the electronic, magnetic, and lattice excitations in the bilayer nickelate La₃Ni₂O₇. Experimental observations show that after entering the spin-density-wave state below 153 K, the A₁g channel exhibits an abrupt electronic spectral gap and an isosbestic point at about 50 meV, whereas the B₁g and B₂g channels are dominated by pronounced two-magnon excitations, indicating two in-plane spin exchange interactions along the Ni–O bonds and their diagonal directions. Calculations based on spin-wave theory further indicate that the B₂g two-magnon mode originates from competition between two bond-diagonal antiferromagnetic interactions mediated by Ni d_{x²−y²} orbitals, while low-energy two-magnon excitations below 10 meV arise from weaker spin moments and support spin disproportionation. The study also observes anomalous softening of the B₁g phonon from 280 K to 4.5 K, suggesting an incipient lattice instability that leads to checkerboard-like breathing modulation. These results link competitive bond-diagonal interactions, spin disproportionation, and lattice instability, providing key elements for understanding the superconducting mechanism of nickelates. arXiv submission processing window: 2026-11-04 00:00 to 2026-11-04 00:00 UTC. ...
arXiv Daily: nickelate superconductors 2026-11-04