LAUSR

The present work aims to investigate the elastic constants and their related mechanical parameters, acoustic wave speeds, piezoelectric coefficients and thermal properties of cubic zinc-blende AlN and their pressure dependence up to 5 GPa. The calculations are performed using the pseudopotential plane-wave method within the frame work of the density functional perturbation theory in the local density approximation for the exchange–correlation functional. The accord between our results and the experimental and previous theoretical data reported in the literature is found to be generally reasonably good. It is found that the surface acoustic wave speeds decrease with increasing pressure for both [100] and [110] crystallographic directions, while both elastic stiffness constants and piezoelectric coefficients increase under applied pressure. The variation of the features of interest as a function of pressure shows almost a linear behavior.