Structural, mechanical and optoelectronic features of cubic MgxCd1−xS, MgxCd1−xSe and MgxCd1−xTe semiconductor ternary alloys: Theoretical investigations using density functional FP-LAPW approach

Abstract

Structural, mechanical and optoelectronic features of cubic MgxCd1−xS, MgxCd1−xSe and MgxCd1−xTe are calculated using density functional FP-LAPW approach. Exchange-correlation potentials are calculated for structural and mechanical properties with WC-GGA and optoelectronic properties with mBJ, EV-GGA and PBE-GGA schemes. Each ternary specimen exhibits thermodynamic stability. In each system, nonlinear decrease in each of the a0, B0, C11, C12 and C44 with increase in Mg-concentration x is observed. Each specimen exhibits elastic anisotropy, ductility and dominancy of ionic bonding. Each binary and ternary specimen is a direct (Γ-Γ) band gap (Eg) semiconductor. In each system, calculated Eg increases nonlinearly with increase in x. Optical excitations from chalcogen-p to Cd-6s, 5p and Mg-4s, 4p contribute intense peaks in each ε2(ω) spectra. Nature of variation of zero-frequency limit in each of the ε1(ω), n(ω) and R(ω) spectra and critical point in each of the ε2(ω), k(ω), σ(ω) and α(ω) spectra with x is opposite and similar, respectively, to the nature of variation of Eg with x.