Optical phonons of hexagonal

The behavior of longitudinal and transverse optical phonons in hexagonal AlxGa1-xN is derived theoretically and experimentally as a function of the concentration x(0≤x≤1). The theoretical approach is based on a modified random element isodisplacement model which considers the interactions with the nearest neighbor and second neighbor atoms. We find 'one-mode' behavior in AlxGa1-xN in which the phonon frequency in general varies continuously and approximately linearly with x. The theoretical simulations are in good agreement with Raman scattering experiments, which also reveal that both the linewidth and intensity of the optical phonons strongly depend on the concentration. copyright 2001 American Institute of Physics