FP‐LAPW investigations of Zn_1–xBe_xS, Zn_1–xBe_xSe and Zn_1–xBe_xTe ternary alloys

Abstract

The ab initio full potential linearized augmented plane wave (FP-LAPW) method within density functional theory was applied to study the effect of composition on the structural and electronic properties of Zn 1-x Be x S, Zn 1-x Be x Se and Zn 1-x Be x Te ternary alloys. The effect of composition on lattice parameter, bulk modulus, band gap and effective mass was investigated. Deviations of the lattice constant from Vegard's law and the bulk modulus from linear concentration dependence were observed for all three alloys. It was deduced that increasing the Be composition in the alloys increases the hardness of the materials. In addition, the calculated band structures showed that the band gap undergoes a direct-to-indirect transition at a given concentration. Using the approach of Zunger and co-workers, the microscopic origins of band gap bowing have been explained. The electron (hole) effective masses were also calculated. The band gap and effective mass were found to vary non-linearly with Be composition.

First principles study of structural and electronic properties of Bex Zn1–xS and Bex Zn1–xTe alloys

“…Our calculated bowing turn out to be -0.16 Å and 2.6971 GPa for Be x Zn 1-x S. These results are in agreement with the theoretical works of Baaziz et al [22]. For Be x Zn 1-x Te we obtained upward and downward bowing parameters equal to -0.1165 Å and 0.33829 GPa for the lattice constant and the bulk modulus, respectively, as compared to the theoretical values of -0.13117 Å and -0.3428 GPa [22]. The deviation from Vegard's law should be mainly due to the lattice mismatch between BeS and ZnS compounds.…”

DFT and X-RAY study of structural, electronic, elastic and optical properties in Be1–XZnXS alloys depending on vegard’s law

“…The calculated data and other theoretical data have been listed in Table 4 [9,21]. Band profiles and band gap values are in agreement with the former studies.…”

“…It is essential to research alloys in detail to advance heterostructures based on these recent material systems. We have studied within AP-LAPW (the full-potential linearized augmented-plane wave) to investigate the structural and electronic properties of alloys composed of beryllium and chalcogens (Zn 1-x Be x S) for the design of blue-green laser diots [9]. In this study, we aim to obtain the optical, electronic properties of Be 1-x Zn x S mixed crystals and elastic constants, like bulk modulus, young modulus, shear modulus, Poisson's ratio, compressibility and B/G by means of Castep program based on density function theory (DFT) and compare the results of the elastic constants obtained via X-ray analyses based on Vegard's law.…”

FP-LMTO Investigation of the Structural and Electronic Properties of Cu<sub>x</sub>Ag<sub>1–x</sub>I Alloys

“…Results from earlier theoretical works are also quoted for comparison. The calculated electron effective masses are in good agreement with those obtained by using the full potential linear augmented plane wave (FP-LAPW) method whin EVGGA approximation [22] which is known to improve the values of the band gaps rather than LDA and GGA [26][27][28]. This agreement disappears in the case of hole effective masses.…”