Anisotropic Spin Stripe Domains in Bilayer La$_3$Ni$_2$O$_7$
N. K Gupta, R. Gong, Y. Wu, M. Kang, C. T. Parzyck, B. Z. Gregory, N. Costa, R. Sutarto, S. Sarker, A. Singer, D. G. Schlom, K. M. Shen, D. G. Hawthorn
The discovery of superconductivity in La$_3$Ni$_2$O$_7$ under pressure has motivated the investigation of a parent spin density wave (SDW) state, which could provide the underlying pairing interaction. Here, we employ resonant soft x-ray scattering and polarimetry on thin films of bilayer La$_3$Ni$_2$O$_7$ to determine that the magnetic structure of the SDW forms unidirectional diagonal spin stripes with moments lying within the NiO$_2$ plane and perpendicular to $\mathbf{Q}_{SDW}$, but without evidence of the strong charge disproportionation typically associated with other nickelates. These stripes form anisotropic domains with shorter correlation lengths perpendicular versus parallel to $\mathbf{Q}_{SDW}$, revealing nanoscale rotational and translational symmetry breaking analogous to the cuprate and Fe-based superconductors, with possible Bloch-like antiferromagnetic domain walls separating orthogonal domains.
Charge stripe and superconductivity tuned by interlayer interaction in a sign-problem-free bilayer extended Hubbard model
School of Physics and Astronomy, Beijing Normal University（北京师范大学物理与天文学院）；Key Laboratory of Multiscale Spin Physics(Ministry of Education), Beijing Normal University（北京师范大学多尺度自旋物理教育部重点实验室）；School of Physics and Institute for Advance Study in Physics, Zhejiang University（浙江大学物理学院及物理高等研究院）
Origin of Spin Stripes in Bilayer Nickelate La$_3$Ni$_2$O$_7$
The Chinese University of Hong Kong（香港中文大学）；Johns Hopkins University（约翰斯·霍普金斯大学）；Stanford University（斯坦福大学）；SLAC National Accelerator Laboratory（斯坦福直线加速器中心）
Spin Waves and Spatially Anisotropic Exchange Interactions in the $\mathrm{S=2}$ Stripe Antiferromagnet Rb$_{0.8}$Fe$_{1.5}$S$_2$
用中子非弹性散射方法研究了绝缘Rb $_{0.8}$ Fe $_{1.5}$ S $_2$在布里渊区的条纹反铁磁序自旋波。自旋波谱很好地描述了海森堡哈密顿与各向异性的面内交换相互作用。对有序矩和自旋涨落进行积分，得到$27.6\pm4.2μ_B^2$ /Fe的总矩平方，与$\mathrm{S \approx 2}$一致。不同于$X$ Fe $_2$ As $_2$（$X=$ Ca，Sr和Ba），其中巡回电子有显着的贡献，我们的数据表明，Rb $_{0.8}$ Fe $_{1.5}$ S $_2$中的这种条纹反铁磁有序相是一个莫特状绝缘体，具有完全本地化的$3d$电子和高自旋基态配置。然而，各向异性交换耦合似乎是普遍的，在条纹相的铁磷属化物和硫属化物。
Gigantic anisotropic uniaxial pressure effect on superconductivity within the CuO2 plane of La1.64Eu0.2Sr0.16CuO4 - strain control of stripe criticality
Universidade de São Paulo（圣保罗大学）；Ruhr-Universität Bochum（波鸿鲁尔大学）；PSI Center for Neutron and Muon Sciences CNM（瑞士保罗谢勒研究所中子与μ子科学中心）；TU Dortmund University（多特蒙德工业大学）
