Metallic Superlattices with Monolayer Modulation

We report the preparation and characterization of sputtered Mo/Ta superlattices where the wavelengths are modulated by integer numbers of atomic monolayers. Resistivity and tunnel junction measurements on Mo/Ta superlattices with wavelengths in the range from 153 atomic planes each of Mo and Ta to the monolayer limit of 1 atomic plane of each are found to be consistent with their structural properties as determined by x-ray analyses. In addition, these results are consistent with earlier studies on the phonon structure of Mo/Ta using Brillouin scattering.