Extracting the crystal electric field levels of Ce-4f1 states in CeB6 by atomic multiplet simulations

The crystal electric field (CEF) is vital in defining the low-energy electronic structure of lanthanide compound, and thus very essential in understanding the many-body physics of the strongly correlated 4 f electrons. Many efforts have been made to determine the low-energy electronic structure of the intrinsically correlated material CeB6 and its derived compounds. In this paper, we performed atomic multiplet (AM) simulations on the Ce-4f1 states in CeB6 and directly fitted them with previously reported resonant inelastic x-ray scattering spectroscopy (RIXS). The simulation results suggest that the discrepancy of excitations energies extracted from Raman spectroscopy and RIXS is a result of intrinsic varied crystal electric field strength, which can be reconciled by considering the enhanced CEF by eliminating the insulating scenario.