Theoretical study of -edge resonant inelastic X-ray Scattering in LaCuO on the basis of detailed electronic band structure

Nomura, Takuji

We study theoretically resonant inelastic X-ray scattering (RIXS) at the Cu -edge in a typical parent compound of high- cuprate superconductors LaCuO on the basis of a detailed electronic band structure. We construct a realistic and precise tight-binding model by employing the maximally-localized Wannier functions derived from a first-principles electronic structure calculation, and then take account of the Coulomb repulsion between electrons at each Cu site. The antiferromagnetic ground state is described within the Hartree-Fock approximation, and take account of electron correlations in the intermediate states of RIXS within the random-phase approximation (RPA). Calculated RIXS spectra agree well with the experimentally observed features including low-energy magnon excitation, - excitations, and charge-transfer excitations, over a wide excitation-energy range. In particular, we stress the importance of photon polarization dependence: the intensity of magnon excitation and the spectral structure of - excitations depend significantly not only on the polarization direction of incident incoming photons but also that of outgoing photons.