Vibrational Spectroscopy of Ordered Oxygen Adlayers on Ni/Cu(001) and Co/Cu(001)Thin Film Systems

摘要

We report surface vibrations in c(2x2) oxygen adlayers on Ni and Co thin films ona Cu (001) substrate measured at gamma by high resolution EELS. For the Ni thin film surface, one phonon peak is measured for varying film thickness from 1.3 ML (monolayer) to 6 ML with a constant energy of 221/cm. For the Co thin film surface, three loss peaks are found, whose relative intensities change as the film thicknesses are varied. One loss peak ca. 520/cm is tentatively assigned to the Fuchs-Kliewer mode of cobalt oxide (CoO). The other two peaks at 317/cm and 376/cm are likely related to different bonding sites. Surface phonons on the p(2 x2) Co thin film (389/cm) and a bulk resonance mode (115/cm) are also reported.