Observation of short- and long-range hybridization of a buried Cu monolayer in Ni

The electronic structure of a Cu monolayer buried in Ni fcc(100) is studied by means of x-ray emission and absorption spectroscopies in combination wi th first principles calculations. The local character of the x-ray probes a llows us to investigate changes in the chemical interaction for these ultra thin film systems. In comparison to bulk Cu, the occupied d states of a bur ied Cu monolayer, as-mapped in the x-ray emission spectrum, remain mostly u naltered. The absorption spectrum on the other hand shows that the empty st ates of the buried Cu monolayer are modified, and instead resemble the unoc cupied electronic density of bulk Ni. These findings agree well with our fi rst principle electronic structure calculations and the results are interpr eted in terms of short- and long-range hybridization.