Daily Overview: This issue contains two studies of nickelates. [1] Neutron scattering resolves single-stripe order and bilayer spin dynamics in ambient-pressure La3Ni2O7, providing experimental evidence about magnetism in the parent compound. [2] Controlling nonhydrostatic stress in La4Ni3O10 promotes zero resistance under enhanced in-plane biaxial compression and separates superconductivity from the low-pressure density-wave phase. The authors use this separation to assess a density-wave quantum-critical pairing mechanism. arXiv announcement date: 2026-10-30.
1. Single-stripe magnetic order and bilayer spin dynamics in single-crystalline La3Ni2O7
- Relevance Score:
5.9561 - Authors: Lixing Chen, Enkang Zhang, Yiqing Hao, Yinghao Zhu, Bingkun Cui, Douglas L. Abernathy, Travis J. Williams, Yoichi Ikeda, Hao Zhang, Feiyang Liu, Wenbin Wang, Qisi Wang, Jun Zhao
- Affiliations: The Chinese University of Hong Kong, Tohoku University, Fudan University, Shanghai Research Center for Quantum Sciences, STFC Rutherford Appleton Laboratory, Oak Ridge National Laboratory
- Link: https://arxiv.org/abs/2605.03448
- Paper page: Single-stripe magnetic order and bilayer spin dynamics in single-crystalline La₃Ni₂O₇
Summary: The study uses La3Ni2O7 single crystals grown by the high-pressure optical floating-zone method and, combining neutron diffraction with inelastic neutron scattering, identifies in the ambient-pressure parent phase a single stripe-type magnetic order at q=(0,0.5,0.5), and measures a spin gap of about 5 meV, in-plane anisotropic excitations, and a pronounced modulation with bilayer periodicity, the latter indicating antiferromagnetic interlayer coupling. The dispersion is described by a bilayer Heisenberg-type model including strong interlayer exchange and competing in-plane exchange; elastic scattering cannot readily distinguish single-stripe from double-stripe order, whereas the inelastic spectra serve as the discriminating basis. Absolute normalization shows that the spin-wave bandwidth is only about 25% that of cuprates, while the local dynamic magnetic susceptibility is enhanced at the corresponding energies, and the total fluctuating moment is comparable to that of cuprates. The results establish a magnetic framework different from that of cuprates and are regarded as relevant to nickelate superconductivity; the paper does not establish a pairing channel, and the role of magnetism in pairing remains a premise to be tested.
2. Separating the Density Wave Phase from Zero-Resistance Superconductivity in La$_4$Ni$_3$O$_{10}$
- Relevance Score:
5.9098 - Authors: P. Puphal, A. Suthar, B. Wehinger, V. Sundaramurthy, T. Priessnitz, M. Knauft, P. Sosa-Lizama, Y.-M. Wu, M. Hepting, J. Nuss, M. Isobe, P. A. van Aken, Y. E. Suyolcu, B. Keimer, H. Takagi, P. Reiss
- Link: https://arxiv.org/abs/2610.38959
- Paper page: Separating the Density Wave Phase from Zero-Resistance Superconductivity in La₄Ni₃O₁₀
Summary: High-quality single crystals of the trilayer Ruddlesden–Popper nickelate La4Ni3O10 were studied using a diamond anvil cell to explicitly tune the nonhydrostatic pressure component, combined with high-pressure electrical transport and synchrotron X-ray diffraction, thereby distinguishing out-of-plane-dominated compression from enhanced in-plane biaxial compression. Enhanced in-plane biaxial compression induced a uniform, reproducible zero-resistance superconducting state at 17.2 and 18.9 GPa, with the required pressure reduced by about 60% compared with previous reports; meanwhile, the density-wave phase under low compression was completely suppressed and separated from the superconducting state, which the authors interpret as effectively ruling out soft quantum critical fluctuations of the density-wave order parameter as a pairing glue in this system. In contrast, out-of-plane-dominated compression only slowly suppressed the density wave, and zero resistance was still not achieved up to 34 GPa, with superconducting signatures being filamentary and inhomogeneous. High-pressure XRD showed that the ambient-pressure monoclinic phase transforms into a tetragonal phase under high pressure, whereas an orthorhombic phase appears as an intermediate under enhanced in-plane compression. On this basis, the authors conclude that in-plane biaxial compression is an effective means to tune nickelate superconductivity, unifies the pressure scales of bilayer and trilayer Ruddlesden–Popper structures, and is linked to results on strained thin films.