Phonon deformation potentials of α-GaN and -AlN:: An ab initio calculation

First-principles density functional theory calculations of the deformation potentials are presented for zone-center phonons in GaN and AlN in the wurtzite structure. Three cases of deformations are considered: biaxial and uniaxial strain along the c axis as well as hydrostatic compression. For the resulting atomic structures the phonon frequencies are determined. The combination of calculations for these deformations allows the derivation of elastic constants and phonon deformation potentials. Good agreement is observed with measured values for GaN. No published values for AlN are available. (C) 2000 American Institute of Physics. [S0003-6951(00)00529-5].