Phonons on II-VI (110) semiconductor surfaces

We have studied the phonon dispersion and density-of-states on the (110) su rface of LI-VT compounds CdTe, ZnTe, and ZnS in their zinc-blende phase by applying the adiabatic bond charge model. The relaxed surface atomic geomet ry and the corresponding bond charge information is obtained from the appli cation of an ab initio pseudopotential calculation. The origins of various surface phonon modes are discussed and their variation for different compou nds are analyzed in terms of the reduced mass and total mass differences. F urthermore, we have related some differences between surface modes on II-VI (110) and III-V (110) in terms of the ionicity factor.