High pressure structural phase transition and elastic properties of yttrium pnictides

We have investigated, the cohesive energies, equilibrium lattice constants, pressure–volume relationship, phase transition pressure (PT), elastic constants and variation of elastic constants with pressure for yttrium pnictides (YX; X=N, P, As and Sb), using an interionic potential theory with modified ionic charge which, includes Coulomb screening effect due to d-electrons. These compounds undergo structural phase transition from NaCl (B1) to CsCl (B2) structure at high pressure (ranges 20–130 GPa). We have also calculated bulk (BT), Young (E), and shear moduli (G), Poisson ratio (υ) and anisotropic ratio (A) in NaCl (B1)-type structure for yttrium pnictides and compared them with other experimental and theoretical results which show a good agreement.