ORBITAL ORDERING IN LaMnO3: CLUSTER MODEL CALCULATION OF RESONANT X-RAY SCATTERING AND X-RAY ABSORPTION AT THE MnL2,3 EDGE

Abstract

We report theoretical results for resonant X-ray scattering (RXS) and linear dichroism (LD) in X-ray absorption spectra at the Mn L 2,3 edge in LaMnO 3, with special attention to the observation of orbital ordering. Calculations were performed on a ( MnO 6)10- cluster with D 4h symmetry, including the effect of intra-atomic multiplet coupling in the Mn ion. Anisotropy effects are also included, through the anisotropic Mn 3d– O 2p hybridization and crystal field parameters for Mn 3d states. The agreement between theory and experiment is good. Moreover, we show that the intensity of the peaks at the L 3 edge are strongly dependent on the Jahn–Teller distortion, while the peaks at the L 2 edge are mostly related to the orbital ordering.