Long-wavelength optical phonons in ternary nitride-based crystals

Abstract
Phonon modes in column-III–nitride ternary semiconductors are investigated theoretically within the modified random-element isodisplacement model. It is found that A1 and E1 branches of optical phonons in wurtzite GaxAl1xN and InxGa1xN exhibit one-mode behavior. This result is explained by the fact that atomic mass of nitrogen is much smaller than those of other atoms.