Date of Award
Doctor of Philosophy (PhD)
Physics and Astronomy
Richard L. Kurtz
I have studied the electronic structure of thin films by photoelectron spectroscopy. My results show that even a monolayer film of Ni/Cu(001) exhibits bulk-like electronic structure and resembles that of bulk Ni. In order to better understand this result, I tracked the sp-band dimension at the Fermi surface of the Ni films for various coverages. For submonolayer coverages of Ni, the sp-band dimension was smaller than that of bulk Cu, but quickly reached that of bulk Ni by 1.2 ML Ni coverage. This continuous decrease implies a charge transfer from the Cu substrate to the Ni film, resulting in a decrease in the filling of the Cu sp-band. This transfer of electronic charge could provide a mechanism for hybridization at the Cu/Ni interface and result in a larger penetration of the film electronic states into the substrate. To quantify the charge transfer, the reverse system of Cu/Ni(001) was studied. Again the sp-band dimension for 45 eV photons was studied as a function of Cu thickness. The change in the sp-band dimension was related to reduced filling in the sp-band of bulk Cu. This corresponded to a reduction of $\sim$0.5 eV in the band-filling of bulk Cu. From the integrated density of states, this was identified to be a charge depletion of $\sim$0.12 electrons/atom for the monolayer film. This shift was observed in core level spectra across the 3p levels, corroborating the assumption.
Subramanian, Krishnan, "Photoemission Studies of Magnetic Systems." (1997). LSU Historical Dissertations and Theses. 6529.