Quantum size and surface effects in the electrical resistivity and high-energy electron reflectivity of ultrathin lead films

Oscillations of the electrical resistivity of thin epitaxial Pb films on Si(111) surfaces and of the intensity of the specular beam in high-energy electron diffraction from these films are reported. They are in part due to a surface effect, the scattering of internal and external electrons at surface steps whose density varies periodically during the growth. In part they are caused by a volume effect, the quantum size effect due to the quantization of the Fermi momentum of the film electrons and of the normal component of the wave vector of the incident electrons, respectively.