Abstract
Oxygen K-edge absorption spectra of carefully characterized samples were measured using a bulk-sensitive fluoresence-yield-detection method. They reveal two distinct pre-edge peaks which evolve systematically as a function of Sr concentration. The measured spectra are quantitatively described by calculations based on the Hubbard model, including local Coulomb interactions and core-hole excitonic correlations. The absorption data are consistent with a description of electronic states based on a doped charge-transfer insulator.
- Received 14 September 1990
DOI:https://doi.org/10.1103/PhysRevLett.66.104
©1991 American Physical Society