Resonant elastic x-ray scattering experiments on the van der Waals anti-ferromagnet NiPS3*

We present an exploration into the magnetic properties of van der Waals (vdW) materials, specifically focusing on the anti-ferromagnetic Mott-insulator NiPS₃.   These materials are at the center of a host of novel types of experiments, however, there are notably few pathways to directly probe their magnetic structure.  Employing resonant elastic X-ray scattering, we examined a single NiPS₃ crystal, revealing unexpected three-dimensional (3D) Heisenberg model characteristics. This finding, reinforced by first-principle theoretical calculations, challenges established norms about magnetic dimensionality in this vdW system.  Additionally, we report progress on experiments on these materials using X-ray Photon Correlation Spectroscopy and X-ray Photon Fluctuation Spectroscopy to analyze their dynamics at time-scales ranging from seconds to femtoseconds.