Phonons on group-III nitride (110) surfaces

Abstract

We have applied the adiabatic bond-charge model within a supercell approach to study the lattice dynamics of group-III nitride (110) surfaces. The structural and electronic information necessary for these calculations is obtained from using the ab initio pseudopotential method. The phonon dispersion curves for the group-III nitride (110) surfaces are presented and compared with each other in detail. From this comparison, it is found that the InN(110) and GaN(110) surfaces show similar dynamical behavior due to their large cation-anion mass differences. It is pointed out that in general surface phonon modes on group-III nitride (110) can be related to their counterparts on non-nitride III-V(110) and II-VI(110) surfaces provided that results are scaled with respect to the reduced mass and lattice constant differences. The rotational phonon mode predicted for other semiconductor surfaces is also identified for the group-III nitride (110) surfaces.