First principles calculations of structure parameters and transition pressures of GaN$_{1-x}$Bi$_x$ alloys

In this work, we have studied the structural properties of GaN$_{1-x}$Bi$_x$ ternary alloys using the pseudopotentiel method. We have calculated properties of these alloys in zinc blende, rocksalt and wurtzite structures at atmospheric and under hydrostatic pressure. The calculated lattice parameters increase by increasing bismuth composition, while a little deviation from Vegard's law is observed. We have shown that for $x$ = 0 and 0.25, the wurtzite phase is the most stable, whereas for Bi concentration 0.375, 0.5, 0.75 and 1 the zinc blende phase is the most stable one. We have calculated for each case the transition pressure and we have found that our calculated values were in good agreement with those in the literature.