Probing electron charge densities with core-level non-resonant inelastic x-ray scattering

Correlated electron systems yield a plethora of fascinating phenomena, 
when the physics is beyond the single particle picture and the 
electron-electron interactions become important. Therefore, the electron 
charge density is one of the key properties for understanding these 
materials.
Core-level non-resonant inelastic x-ray scattering (core-level NIXS), or 
x-ray Raman scattering (XRS), is commonly used to perform soft x-ray 
absorption spectroscopy in a bulk sensitive way. With XRS, however, one 
can also overcome the dipole selection rules and access higher 
multipoles by tuning the momentum transfer.
I will present how these higher multipoles can be utilized to give an 
unique insight into electron charge densities and show results for 
different cubic materials measured at P01 [1-3].

[1] Europhysics Letters 117 17003 (2017)
[2] Physical Review Letters 120 016402 (2018)
[3] Nature Physics 15 559 (2019)