Exact diagonalization results for resonant inelastic x-ray scattering spectra of one-dimensional Mott insulators

We examine the momentum-dependent excitation spectra of indirect as well as direct resonant inelastic x-ray scattering (RIXS) processes in half-filled (extended) Hubbard rings. We determine the fundamental features of the ground-state RIXS response and discuss the experimental conditions that can allow for the low-energy part of these features to be distinguished in one-dimensional copper-oxide materials, focusing particularly on the different magnetic excitations occurring in indirect and direct RIXS processes. We study the dependence of spin and charge excitations on the choice of and detuning from resonance. Moreover, final-state excitation weights are calculated as a function of the core-hole potential strength and lifetime. We show that these results can be used to determine material characteristics, such as the core-hole properties, from RIXS measurements.