Dynamical and thermodynamic properties of III-nitrides

In this work, we have calculated ab initio the equation of state, the principal phonon modes, the effective charges and the temperature dependence of the specific heat for the III-Nitrides, by using the density-functional theory within the local density approximation, plane wave expansions and the pseudopotential method. A good agreement with the experiment and other calculations is obtained, whenever a comparison is possible. From our results, we speculate whether these systems undergo, by a second-order phase transition, from the wurtzite structure to the zincblende one. q 2003 Elsevier Science Ltd. All rights reserved.