MODIFICATION OF PHONON SPECTRAL DENSITIES OF THE (001) COPPER SURFACEDUE TO COPPER ADATOMS BY MOLECULAR-DYNAMICS SIMULATION

Phonon spectral densities of the (001) copper surface containing coppe r adatoms have been calculated at various temperatures using molecular dynamics simulation. The results reveal that the presence of adatoms is manifested mainly by the appearance of new dispersionless peaks whi ch are broadened and shifted to lower energies as the temperature incr eases. The existent experimental results, as well as lattice dynamics, ab initio calculations and other simulations in the case of a clean s urface, are in good agreement with our predictions.