HIGH-ENERGY-SPECTROSCOPY STUDIES OF A CHARGE-TRANSFER INSULATOR - X-RAY-SPECTRA OF ALPHA-FE2O3

X-ray emission and absorption spectra of alpha-Fe2O3 have been arranged on a common binding-energy scale and compared with results of multiplet theory and cluster calculations. In the case of the Fe L-alpha emission and the Fe K absorption, the information content of x-ray spectroscopy has been further increased by measuring and analyzing linearly polarized spectra. The results of the x-ray spectroscopic investigations and their comparison with the theory complement the findings of other types of high-energy spectroscopy and seems to provide good support for the validity of certain cluster theories. Especially, x-ray spectra reflect the strong influence of correlation and charge-transfer effects on the electronic structure of alpha-Fe2O3 and support the suggestion that this compound should belong to the class of charge-transfer insulators.