Structural, elastic, and electr onic properties of CuCl<inf>x</inf>Br<inf>(1-x)</inf> compounds under pressure

Abstract

We have applied the pseudo-potential plane wave (PP-PW) method to study the structural, elastic, and electronic properties of CuClxBr(1-x) under high pressure using the generalized gradient approximation (GGA). The effect of Cl substitutional impurities (x) on the lattice parameters for both the GGA and virtual crystal approximation (VCA) approaches were studied. The pressures at which the compounds CuClxBr(1-x) undergo a structural phase transition from ZnS type to NaCl type Pt were calculated. The elastic constants at various pressures in the 0 < x < 1 composition range were presented. The longitudinal-wave mode speed (VL) and transverse-wave mode speed (VT) in CuClxBr(1-x) propagating in the [100], [110], and [111] directions at zero pressure for various Cl compositions (x) in the range 0-1 were investigated. The band structure and band gap-pressure coefficients are also given. The calculated effective masses of electrons and heavy and light holes in the material under study for different concentrations x are presented.