Momentum-resolved resonant inelastic X-ray scattering as a novel tool to study electronic structure of complex insulators

Well-developed momentum-resolved spectroscopies such as photoemission or neutron scattering cannot probe the full charge gap in insulators. We demonstrate that charge excitations across the full gap in a Mott insulator can be studied using high resolution inelastic X-ray scattering in a momentum-resolved manner which can provide momentum-resolved information about the unoccupied electronic band. We also briefly mention some advantages this technique has over other spectroscopies to study electronic structure of matter.