Microscopic analysis of resonant inelastic X-ray scattering in orbital-ordered KCuF

Nomura, Takuji

We analyze resonant inelastic X-ray scattering (RIXS) at the Cu edge in a typical orbital-ordered compound KCuF on the basis of a microscopic theory. Spectral shape and its dependence on polarization direction and momentum transfer of photons are explained consistently with experimental data within our microscopic calculation. According to our microscopic orbital-resolving analysis, high-energy spectral weights (above 5 eV) originate from charge-transfer excitations related to the Cu- orbitals, while the low-energy weights (below 2 eV) originate from the - orbital excitations among the five Cu- orbitals. We assign specifically the RIXS weights to microscopic orbital-excitation processes, beyond the previous phenomenological assignment based on symmetry properties.