Using High-Pressure Conditions to Access Novel Structures and Engender Magnetic Control in Layered Lanthanide Materials

A rational approach to designing the next generation of quantum magnetic materials requires hypothesis-driven synthesis. Yet, the complex phase space of solid-state systems and the small energy scales that determine magnetic order are such that subtle changes in composition can drastically change the structure and properties of the resulting material. In comparison, pressure provides an incrementally tunable vector, serving to increase orbital overlap and leading to more significant covalent and metallic interactions. In this work, we describe our multimodal approach combining high-pressure synthesis with spectroscopy and calculations to bring new chemical insight into the discovery of layered materials containing lanthanides primed to exhibit exotic magnetic behaviors. To realize promising synthetic targets, we turned to both traditional solid-state techniques as well as high-pressure experiments in diamond anvil cells. We note an established tendency towards layered structures in lanthanides halides that depends on the formal valence state of the lanthanide metal. Crucially, dimensionality is known to be sensitive to applied pressures, and can be harnessed to tune the structure of lanthanide systems to promote low-dimensional motifs. We will discuss our burgeoning chemical intuition for structure formation and metastability in this space, as well as present our ongoing efforts towards correlating new structures with magnetic properties both at ambient pressures and under high-pressure synthesis conditions.