Optical phonons in cubic AlxGa1-xN approached by the modified random element isodisplacement model

Abstract

The behavior of longitudinal and transverse optical phonons in cubic AlxGa1-xN are derived theoretically as a function of the concentration x(0 ≤ x ≤ 1). The calculation is based on a Modified Random Element Isodisplacement model which considers the interactions from the nearest neighbor and second neighbor atoms. We find one-mode behavior in AlxGa1-xN where the phonon frequency in general varies continuously and approximately linearly with x.