Isostructural phase transition in InN wurtzite

Using the first-principles total-energy pseudopotential method, we study the behavior of wurtzite InN under hydrostatic pressure by relaxing all the structural parameters at all volumes considered. Our calculations point to the existence of a second order isostructural phase transition which occurs in the same pressure range as the wurtzite-NaCl first order phase transformation, and which completely changes the behavior of the structural parameters at higher pressures. We propose that this phase transition, which still awaits experimental observation, is induced by second-neighbor interactions between indium atoms and can be considered as a pretransitional effect inducing the reconstructive first order transition.