Phonons in a W-Mo(001) superlattice

Electronic structure of Nb-Ta (001) superlattices

“…The oscillatory behaviour found in figures 2 and 3 is analogous to that found for phonons in W-MO superlattices [24] and electronic states in GaAs-A1As superlattices [8]. This is seen to constitute a characteristic feature of superlattice states, irrespective of specific cases.…”

“…Exactly the same kind of behaviour has also been found for states near band edges for phonons in transition-metal superlattices [24] and electrons in semiconductor superlattices [8]. Thus this great diversity in spatial behaviour is independent of the specific type of state or elementary excitation.…”

“…The interactions at the interfaces are first taken as the mean of the bulk interactions of the two crystals and then changed in order to determine their influence on the electronic structure. It has been found for elastic waves [22,23] and for phonons [24] that the relative thicknesses of the constituent slabs play an important role in the dispersion relation and the LDOS of the superlattice modes and, as a consequence, in their spatial confinement. We shall investigate this issue for the electronic structure of transitonmetal superlattices.…”

Phonons in (001) Mo/W/Mo and W/Mo/W layer structures

“…The study of the W/Mo/W and Mo/W/Mo systems is presented in Section 4, and conclusions are summarized in Section 5. We employ the notation and layer indexing explained in detail in [3].…”

“…We shall employ instead force-constant models including central and angular interactions up to third neighbours, which give a reasonably accurate description of bulk phonons. rithms are the same as for the superlattices [3,5,6] and will not be repeated here.…”