First-principle investigations of structural, electronic, thermal, and mechanical properties of AlP1-xBix alloys.

CONTEXT: In this work, a comprehensive study concerning the physical properties of ternary alloys system (AlP1-xBix) at different concentrations is presented. The obtained results from our first-principle calculations are compared with previously reported studies in the literature and discussed in detail. Our computed results are found in a nice agreement where available with earlier reported results. Electronic band structures at the above-mentioned concentrations are also determined. Likewise, the impact of the varying temperature and pressure on Debye temperature, heat capacity, and entropy is analyzed as well. Furthermore, elastic constants and related elastic moduli results are also computed. Our results show that alloys are stable and found to be in brittle nature. This is the first quantitative study related to ternary alloys (AlP1-xBix) at mentioned concentrations. We soon expect the experimental confirmation of our predictions. METHOD: The calculations are performed, at concentrations x=0.0, 0.25, 0.5, 0.75, and 1.0 by using the "full potential (FP) linearized (L) augmented plane wave plus local orbital (APW+lo) method framed within density functional theory (DFT)" as recognized in the "WIEN2k computational code". The "quasi-harmonic Debye model" approach is employed to determine the thermal properties of the title alloys.

Analysis of phase stability, elastic, electronic, thermal, and optical properties of Sc1-xYxN via ab initio methods.

Understanding the physical properties of a material is crucial to know its applicability for practical applications. In this study, we investigate the phase stability, elastic, electronic, thermal, and optical properties of the ternary alloying of the scandium and yttrium nitrides (Sc1-xYxN) for different compositions. To do so, we apply a "density functional theory (DFT)" based scheme of calculations named as "full potential (FP) linearized (L) augmented plane wave plus local orbitals (APW + lo) method" realized in the WIEN2k computational package. At first, the phase stability of the investigated compositions of the mentioned alloy is determined. The analysis of our calculations shows that Sc1-xYxN alloy is stable in rock salt crystal structure for all investigated compositions. Next to that, the elastic properties of the rock-salt phase of the studied ternary alloy Sc1-xYxN at all above said compositions were done at the level of "Wu-Cohen generalized gradient approximation (Wu-GGA)" within DFT. However, Trans-Blaha (TB) approximation of the "modified Becke-Johson (mBJ)" potential is also used in combination with Wu-GGA where the thermal properties are calculated at the level of the "quasi-harmonic Debye model." The obtained results for the absorption coefficients, and optical bandgap, represent that the title alloy may be a suitable candidate for the applications in optoelectronic devices.

Phosphide in gallium bismuth: structural, electronic, elastic, and optical properties of GaPxBi1-x alloys.

The structural, electronic, elastic, and optical properties of ternary alloys GaPxBi1-x as a function of phosphorus concentration were studied using ab initio calculations. We have used the full-potential linearized augmented plane wave method-based density functional theory. The potentials have been described by the generalized gradient and modified Becke-Johnson approximations. Results on lattice parameters, energy band gap, bulk modulus, elastic, and optical properties are reported. They are in good agreement with available theoretical and experimental data. Moreover, the dependence of structural and electronic properties on the composition has been analyzed. A deviation from linearity is observed for the lattice constant and the bulk modulus. In addition, the elastic constants and moduli were calculated and used to examine the mechanical stability. Both parts of dielectric-function and other optical parameters have been analyzed.

Structural, electronic, and optical properties of the gallium nitride semiconductor by means of the FP-LAPW method.

In the present paper, the structural, electronic, and linear optical properties of different phases of the gallium nitride (GaN) have been investigated. The zinc blende and wurtzite phases of the GaN have been studied using the full-potential linearized augmented plane wave method (FP-LAPW). In our study, many approximations have been used, such as the local density approximation (LDA), the generalized gradient approximation (GGA), the Engel and Vosko generalized gradient approximation (EV-GGA), and the modified Becke-Johnson (mBJ) potential exchange. As a result, we found a very good agreement with literature experimental results for the energy band gap using the mBJ approximation with a scaling factor of 98% and 80% for the zinc blende and wurtzite phases, respectively.

Phase stability, mechanical, electronic, magnetic and optical properties of tetragonal and cubic M3V (M: Pd, Pt) structures.

The full potential linearized augmented plane wave (FP-LAPW) method was used to investigate the ground states as well as the mechanical, electronic, magnetic and optical properties of M3V (M: Pd, Pt) compounds. The generalized gradient approximation (GGA) of Perdew-Burke and Ernzerhof (PBE-GGA) is employed to treat the exchange-correlation potential for all the calculations except for structural properties where both Wu and Cohen generalized gradient approximation (WC-GGA) and Perdew and Wang local spin density approximation (LSDA) have been added. The cohesive energies, the formation enthalpies and the densities of states at the Fermi level N(EF) show that the D022 structure is more stable than D023 and L12. The lattice parameter and bulk modulus results agree well with the available experimental measurements and theoretical predictions. The elastic and mechanical properties are predicted and show that both compounds exhibit ductile behavior. Furthermore, our calculations of Debye and melting temperatures are in good agreements with experimental results reported in the literature. The densities of states (DOS) show that strong d-d hybridization is behind the formation of the pseudogap at the Fermi level. The contours of the valence charge densities show combinations of metallic and covalent bonds. The number of bonding electrons per atom nb, the electronic specific heat coefficient γ, and the electron-phonon coupling constant λ, are determined. The obtained values of the magnetic moments and polarization coincide with the reported values for both D022 and L12 structures. Moreover, the optical properties, including the dielectric functions, extinction coefficient K(ω), reflectivity coefficient R(ω) and energy loss function L(ω) are studied in the range of 0-14 eV.

Phase stability and optoelectronic characteristics of Ba1-xBexS: a DFT-based simulation.

The structural stability and optoelectronic properties of the ternary Ba1-xBexS alloys along with the pure binary compounds BaS and BeS in the rock-salt (B1) and zinc-blende (B3) phases were investigated by the density functional theory (DFT) within the full-potential linearized augmented plane wave (FP-LAPW) method implemented in the Wien2k package. The generalized gradient approximation of Wu and Cohen (WC-GGA) was used for the exchange-correlation potential (Vxc) to compute the equilibrium structural parameters, lattice constant (a), and bulk modulus (B). In addition to the GGA approach, the modified Becke-Johnson potential of Tran and Blaha (TB-mBJ) scheme coupled with the spin-orbit interaction was used to calculate the band gap energies. Results reveal that BaS, Ba0.75Be0.25S, and Ba0.5Be0.5S compounds are stable in the rock-salt phase, while Ba0.25Be0.75S and BeS are found to be stable in the zinc-blende phase. The computed results for the band structures and optical constants are compared with other available theoretical calculations and experimental measurements.

Structural, electronic and thermal properties of AlxGa1-xAs ternary alloys: Insights from DFT study.

In this research paper, we studied the structural, electronic and thermal properties of the zinc blende ternary alloys (AlxGa1-xAs) by the use of first-principles calculations based on FP-LAPW method (Full Potential Linear Augmented Plane Wave) within DFT (Density Functional Theory). Basically, the impact dependence of the lattice constants, band gaps, bulk moduli, heat capacities, Debye temperatures and mixing entropies on the composition x were investigated for different values of x (x = 0, 0.25, 0.5, 0.75, and 1). The computed ground state properties for the parent binary compounds are in reasonable agreement with the available experimental and theoretical results. It is shown that the lattice constant demonstrated a marginal deviation for AlxGa1-xAs alloy from Vegard's law. It was observed for the studied alloy that significant deviation of the bulk modulus from LCD (Linear Concentration Dependence). Moreover, it was found that the variation of the energy band gap as function of composition is linear via the mBJ approximation. The thermal parameters of these alloys were investigated by means of the quasi-harmonic Debye model.

First principle calculations of structural, electronic, thermodynamic and optical properties of Pb(1-x)Ca(x)S,Pb(1-x)Ca(x)Se and Pb(1-x)Ca(x)Te ternary alloys.

Using first principles total energy calculations within the full potential linearized augmented plane wave (FP-LAPW) method, we have investigated the structural, electronic, thermodynamic and optical properties of Pb(1-x)Ca(x)S, Pb(1-x)Ca(x)Se and Pb(1-x)Ca(x)Te ternary alloys. The effect of composition on lattice parameter, bulk modulus, band gap, refractive index and dielectric function was investigated. Deviations of the lattice constants from Vegard's law and the bulk modulus from linear concentration dependence were observed for the three alloys. Using the approach of Zunger and co-workers, the microscopic origins of band gap bowing have been detailed and explained. The disorder parameter (gap bowing) was found to be mainly caused by the chemical charge transfer effect. On the other hand, the thermodynamic stability of these alloys was investigated by calculating the excess enthalpy of mixing, ΔH(m), as well as the phase diagram. It was shown that all of these alloys are stable at low temperature. The calculated refractive indices and optical dielectric constants were found to vary nonlinearly with Ca composition.