  We present a method for density-functional modeling of metallic overlayers
grown on metallic supports. It offers a tool to study nanostructures and
combines the power of self-consistent pseudopotential calculations with the
simplicity of a one-dimensional approach. The model is applied to Pb layers
grown on the Cu(111) surface. More specifically, Pb is modeled as stabilized
jellium and the Cu(111) substrate is represented by a one-dimensional
pseudopotential that reproduces experimental positions of both the Cu Fermi
level and the energy gap of the band structure projected along the (111)
direction. The model is used to study the quantum well states in the Pb
overlayer. Their analysis gives the strength of the electron confinement
barriers at the interface and at the surface facing the vacuum. Our results and
analysis support the interpretation of the quantum well state spectra measured
by the scanning tunneling spectroscopy.
