Orbital-overlap-driven hybridization in 3d-transition metal perovskite oxides LaMO3 (M = Ti-Ni) and La2CuO4

Abstract

The wide tunability of strongly correlated transition metal (TM) oxides stems from their complex electronic properties and the coupled degrees of freedom. Among the perovskite oxides family, LaMO₃ (M = Ti-Ni) allows an M-dependent systematic study of the electronic structure within the same-structure-family motif. While most of the studies have been focusing on the 3d TMs and oxygen sites, the role of the rare-earth site has been far less explored. In this work, we use resonant inelastic X-ray scattering (RIXS) at the lanthanum N_4,5 edges and density functional theory (DFT) to investigate the hybridization mechanisms in LaMO₃. We link the spatial-overlap-driven hybridization to energetic-overlap-driven hybridization by comparing the RIXS chemical shifts and the DFT band widths. The scope is extended to highly covalent Ruddlesden-Popper perovskite La₂CuO₄ by intercalating lanthanum atoms to rock-salt layers. Our work evidences an observable contribution of localized lanthanum 5p and 4f orbitals in the band structure.

Understanding the hybridization due to orbital overlap in solids allows justification for adjusting electron correlation and hopping integral under the Hubbard model. This work links spatial-overlap-driven to energetic-overlap-driven hybridization from perovskite oxides by resonant inelastic X-ray scattering at La N_4,5 edges.