Magnetism and electronic structure of actinides tuned by ionicity

The project is based on the idea that the 5f magnetism in light actinides can be tailored by reducing the hybridization between their 5f and 6d states by involving the 6d states in polar bonds with ligands. This mechanism can boost magnetic ordering temperatures, as shown earlier for U hydrides, and even reach up to room temperatures, as demonstrated in UCu₂P₂ under pressure. Modification of composition of U hydrides and selected ternary compounds, synthesized both as single crystals and as thin films, combined with application of external pressure, will induce variations of magnetic, transport, and thermodynamic properties, measurements of which will be accompanied by spectroscopic investigations (XPS, UPS, BIS, XAS) with the goal to identify the charge transfer. First-principles calculations will be used to understand the observed trends and to guide the materials selection. Development of advanced many-body methods, reflecting electron-electron correlations and different types of excitations, will enable us to link more accurately the ground-state properties with spectroscopies.