Probing high-energy spin fluctuations in iron pnictide superconductors and the metal-insulator transition in rare-earth nickelates by soft X-ray RIXS

Program Description

Resonant inelastic X-ray scattering (RIXS) is a photon-in/photon-out spectroscopic probe of excitations from the electronic ground state of correlated materials involving lattice, charge, orbital and spin degrees of freedom. In this talk, we show how RIXS at the Fe L3 edge is measuring collective magnetic excitations that are persistent for under-, nearly optimal- and over-doping across the phase diagram of iron pnictide superconductors. Furthermore, we employed RIXS maps vs. incident and transferred photon energies to reveal that the metal-to-insulator transition (MIT) undergoing rare-earth (Re) nickelates ReNiO3 assume a Ni 3d8 electronic configuration with holes in the surrounding oxygen ligands.