High pressure electronic properties in the light of inelastic X-ray scattering From magnetic collapse to quantum criticality

The properties of solids are strongly modified at high pressure. Not only their structure is affected as a direct consequence of the compressed lattice, but also their electronic and magnetic properties as pressure alters significantly the electron density and orbital overlap, thus the electronic localization and hybridization. We present here high pressure experiments using resonant inelastic x-ray scattering. RIXS in the high energy range (≥5keV) has appeared as a powerful probe of the electronic properties under extreme conditions. It is chemically and orbitally selective while showing an intrinsic resolving power spectacularly larger than standard spectroscopic probes. Results will be briefly presented in 3d metals and f-electron systems. The behavior of 3d electrons under pressure will be explored in the light of magnetic collapse transitions; We will comment on f-electron delocalization, especially when approaching a Kondo anomaly or a quantum critical point; Pressure dedicated setups are also discussed.