Magnetic and Charge Order in Transition Metal Dichalcogenide Heterostructures

Next-generation electronic devices will exploit correlated electronic phenomena in quantum materials to encode information for ultra-fast, ultralow-power, and non-volatile storage and retrieval. Spin–spin correlations in exotic magnetic materials are one basis for this new paradigm of compact, energy-efficient electronic systems, but these will require a nanoscale control over long-range magnetic ordering. Conceptually, this may be realized by designing materials that are inherently two-dimensional in their atomic connectivity, or by harnessing nanoscale, non-collinear spin textures in three-dimensional crystals. Likewise, electronic correlations that produce complex charge order can be manipulated to exhibit multi-state resistance phenomena, analogous to phase change materials, but without fatigue.<br/>This talk will describe how transition metal dichalcogenides (TMDs) intercalated with open-shell transition metals represent a family of materials allowing fine control over the chemical and electronic structure of a magnetic material to tailor the interplay between (anti)ferromagnetic exchange, magnetocrystalline anisotropy, and anisotropic exchange (Dzyaloshinskii–Moriya interactions) to bring about exotic magnetic orders in two-dimensional (2D) materials or bulk crystals. The talk will show how soft-chemical methods can be used to prepare the highly coercive 2D ferromagnetic intercalation compound, Fe_xTaS₂, and the use of angle-resolved photoemission spectroscopy to understand differences in chiral helimagnetic order in related 3D compounds, Cr_1/3NbS₂ and Cr_1/3TaS₂. The role of intercalant disorder on magnetic order will be explored in these chiral helimagnets as well as the intrinsically disordered Fe_0.17ZrSe₂. Finally, the talk will show how endotaxial polytype heterostructures of TaS₂ enable multistate resistivity and chirality switching of charge density wave phases.