Planar Force-Constant Method for Lattice Dynamics of Cubic III-Nitrides

Using the density-functional theory within the Full Potential Linear Augmented PlaneWave (FP-LAPW) method, we have calculated, in this work, the equation of state, the e ective charges and the phonon dispersion along [100] and [111] directions for the cubic III-Nitrides(c-BN, c-AlN, c-GaN and c-InN), including hydrostatic strains dependence. A good agreement with the micro-Raman scattering experiment is obtained for the phonon modes at . Our results show that, for c-InN case, the apparent discrepancy between the known experimental results is a consequence of hydrostatic e ects on the sample due to di erences of the used Raman methods.