Electronic and vibrational properties of group-III nitrides: Ab initio studies

We present first-principles calculations based on pseudopotentials and the density functional theory. Structural, electronic and vibrational properties are investigated. The influence of strain and alloy effects is also discussed. Examples for novel exciting results obtained from such calculations are the energy gap of InN, the spontaneous polarization fields, the phonon modes of short-period superlattices, the deformation potentials of the Raman modes, and the gap bowing parameter of InGaN in the entire composition range. (orig.)