Time evolution of the elementary excitations in a photo-excited electron-doped cuprate via tr-RIXS

Investigating the ultrafast dynamics in photo-excited quantum materials is a topic of strong interest in materials science research. To date, available time-resolved probes have revealed information about the lattice, symmetry, and electronic band structure. However, the information about the collective excitations in energy-momentum space, such as magnons and plasmons, are largely unavailable due to the lack of a suitable method. The advent of high repetition rate x-ray free-electron lasers enables time-resolved resonant inelastic scattering (RIXS) experiments, which accesses elementary excitations associated with the magnetic, charge, orbital, and lattice degrees of freedom, thus providing the previously missing pieces of information. In this presentation, I will present our tr-RIXS measurement on the electron-doped cuprates Nd_2-xCe_xCuO₄. A photoexcitation-induced, change of the paramagnon, plasmon, and orbital excitations spectrum were observed. The momentum and time dependence will be discussed.