Ab initiostudy of structural, dielectric, and dynamical properties of GaN

We report first-principles calculations of the structural, dielectric, and lattice-dynamical properties for wurtzite and zinc-blende GaN. The structural properties are calculated using a plane-wave-pseudopotential method of the density-functional theory. A linear-response approach to the density-functional theory is used to derive Born effective charges, dielectric constants, phonon frequencies, and eigenvectors. The results are discussed in terms of ionic and covalent bonding. The computed values are in reasonable agreement with experimental data.