PNNL

Abstract

Metal and oxygen core-level Auger and photoemission spectra have been measured from ultra-thin epitaxial films of Cr2O3 and Fe2O3 on Pt(111). The binding energy shifts of monolayer films relative to thicker films reveal a much smaller extent of screening by the metal substrate than that reported earlier for MgO/Ag(001). This finding suggests that the higher degree of bond covalency in Cr2O3 and Fe2O3 relative to MgO results in more effective intrinsic screening of charge transfer processes, rendering the metal much less effective for extrinsic screening. As a result, the metal is expected to have a negligible effect on the optical, electronic and magnetic properties of the oxide.