Effect of covalency on high pressure phase transition and elastic behaviour of compound semiconductors: Gallium Pnictides and their alloys

We present the results of our calculations on phase transition and elastic properties of Gallium Pnictides by taking three-body interaction potential model, which is modified by taking covalency effect. Phase transition pressures are associated with a sudden collapse in volume showing the occurrence of first order phase transition. The elastic constants are also reported. Our model is able to explain Cauchy violation. The present study is extended to Gallium Pnictide alloys GaPxAs1−x, GaAsxSb1−x and GaPxSb1−x by using Vegard’s law. Our results are in general in good agreement with experimental and theoretical data where available.

► We have investigated the high-pressure structural transition of Gallium Pnictides.
► A modified model (MIPM) (including the covalency effect) has been developed.
► Phase transition pressures are associated with a sudden collapse in volume.
► Our model is able to explain Cauchy violations.
► We have extended our study to alloys of these Pnictides successfully.