Structural phase transformations of GaN and InN under high pressure

We present the results of an ab initio study of the relative stability of structural phases of GaN and InN materials at high pressures. Both the local density and generalized gradient approximations for the exchange-correlation potential have been used in the calculations. The wurtzite, zinc-blende and rocksalt structures are considered. Comparisons with the available experimental data reveal a roughly better agreement with respect to previous calculations. In many cases, the generalized gradient approximation results are found to differ significantly from those of the local density approximation.