Collective charge excitations in Ca2RuO4

The goal of the proposed experiment is to characterize the electronic dynamics in the correlated 4d oxide
Ca2 RuO4 (CRO) with inelastic X-ray scattering (IXS). We will measure the dynamical structure factor
S(⃗q, ω) of CRO in the low/intermediate and high q ranges. The former range containts excitations that
contribute to the dynamical screening of the Coulomb interaction and hence are a factor determining the
existence and magnitude of the band gap. By comparing the results with theoretical calculations, we will
be able to analyze the influences of the long and short range parts of the Coulomb interaction on the
electronic structure of CRO and obtain results generalizable to other ruthenates. In the high q regime
we probe the on-site spin-conserving crystal field excitations revealing information on the local electronic
structure.