Preferred Abstract (Original):
First-principles calculations are carried out to perform the structural
properties using two dimensional search of equation of state (EOS),
elastic constants and thermodynamic properties for zinc-blende (ZB) and
wurtzite (WZ) phases of CdSe
xTe
1−x alloys for all compositions
x
(x = 0, 0.25, 0.5, 0.75, 1). We have used the full-potential linearized
augmented plane wave (FP-LAPW) method within the density functional
theory (DFT), which has been implanted in the WIEN2k code, along with
the improved generalized gradient approximation (PBE-GGA) to treat
exchange-correlation functional. The mechanical and thermodynamic
properties of CdSe
xTe
1−x alloys are studied using
the optimized lattice parameters from two dimensional search of EOS at
zero pressure. The ZB and WZ phases of the ternary CdSe
xTe
1−x
alloys are found to be mechanically stable within PBE-GGA
exchange-correlation over all the range of the Te concentrations (x = 0,
0.25, 0.5, 0.75, 1). We have found that the CdSe is mechanically the
strongest material in the ternary CdSe
xTe
1−x
alloys. We concluded that the calculated values of Cauchy pressure and
Poisson's ratio predict that the ionic bonds for both ZB and WZ phases
of CdSe
xTe
1−x ternary alloys are more dominant for all compositions of
x(x = 0,
0.25, 0.5, 0.75, 1) within PBE-GGA exchange-correlation. Our results
exhibit a non-linear relationship between elastic constants and Se
concentrations. Moreover, the elastic properties of cubic (ZB) and
hexagonal (WZ) phases of CdSe
xTe
1−x alloys,
including elastic constants, bulk and shear moduli are calculated and
compared with available theoretical and experimental results, good
agreement was found.