The first-principles full-potential linearized augmented plane-waves with local orbitals approximation within the density functional theory is used to treat in detail the structural, elastic, and electronic properties of new Pb _{1− x} Ce _x Y (Y  =  S, Se, and Te) alloys at different concentrations ( x  =  0.25, 0.50, and 0.75). The generalized gradient approximation of calculations show that the ground stable state of Pb _{1− x} Ce _x Y alloys is in rock-salt structure, where the equilibrium structural parameters such as, lattice constant, bulk modulus, and its first pressure derivative are performed and compared to the previous theoretical and experimental data. The elastic study is considered to determine the elastic moduli C ₁₁, C ₁₂, and C ₄₄ of the cubic crystal. Through the obtained results of the elastic moduli, the derivative mechanical moduli includi...

The alkaline earth metal chalcogenides are being intensively investigated because of their advanced technological applications, for example in photoluminescent devices. In this study, the structural, electronic, thermodynamic and thermal properties of the BaSe _{1− x} Te _x alloys at alloying composition x = 0, 0.25, 0.50, 0.75 and 1 are investigated. The full potential linearized augmented plane wave plus local orbital method designed within the density functional theory was used to perform the total energy calculations. In this research work the effect of the composition on the results of the parameters and bulk modulus as well as on the band gap energy is analyzed. From our results, we found a deviation of the obtained results for the lattice constants from Vegard’s law as well as a deviation of the value of the bulk modulus from the linear concentration dependence. We also carried out a microscopic analysis of the origin of the band gap ...

In this paper, we investigated the structural, electronic and optical properties of InAs, InN and InP binary compounds and their related ternary and quaternary alloys by using the full potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). The total energies, the lattice parameters, and the bulk modulus and its first pressure derivative were calculated using different exchange correlation approximations. The local density approach (LDA) and Tran–Blaha modified Becke–Johnson (TB-mBJ) approximations were used to calculate the band structure. Nonlinear variations of the lattice parameters, the bulk modulus and the band gap with compositions x and y are found. Furthermore, the optical properties and the dielectric function, refractive index and loss energy were computed. Our results are in good agreement with the validated experimental and theoretical data found in the literature.

In the present work, we investigate the structural, optoelectronic and thermoelectric properties of the YLi ₃ X ₂ ( X = Sb, Bi) compounds using the full potential augmented plane wave plus local orbital (FP-APW+lo) method. The exchange–correlation potential is treated with the generalized gradient approximation/local density approximation (GGA/LDA) and with the modified Becke–Johnson potential (TB-mBJ) in order to improve the electronic band structure calculations. In addition, the estimated ground state properties such as the lattice constants, external parameters, and bulk moduli agree well with the available experimental data. Our band structure calculations with GGA and LDA predict that both compounds have semimetallic behaviors. However, the band structure calculations with the GGA/TB-mBJ approximation indicate that the ground state of the YLi ₃Sb ₂ compound is semiconducting and has an estimated indirect band gap ( Γ<...

The electronic and magnetic properties of Heusler compounds X ₂YZ and XYZ (X = Co, Ni, Pt, Fe; Y = Mn, Cr, Vi; Z = Al, Sb, Ga) are investigated by using the density functional theory with generalized gradient approximation (GGA), GGA plus U (LSDA+U), and modified Becke−Johnson (mBJ) exchange potential. It is found that the half-metallic gaps are generally widened reasonably by LSDA+U and mBJ as compared to the conventional GGA. For the Co-based Heusler compounds the inclusion of U in GGA leads to a larger minority band gap while it is destroyed for Fe ₂VAl and NiMnSb. The magnetic properties of Co ₂VSi and Co ₂VSn are well defined within LSDA+U and mBJ with an exact integer value of magnetic moment. The band gaps of Fe ₂VAl and CoMnSb given by mBJ are in good agreement with the available experimental data of x-ray absorption spectroscopy. Except for the reasonably larger band gap, the mBJ band structure is almost same as that of ...

The structural, electronic, and magnetic properties of the Nd-doped Rare earth aluminate, La _{1− x} Nd _x AlO ₃ ( x = 0% to 100%) alloys are studied using the full potential linearized augmented plane wave (FP-LAPW) method within the density functional theory. The effects of the Nd substitution in LaAlO ₃ are studied using the supercell calculations. The computed electronic structure with the modified Becke–Johnson (mBJ) potential based approximation indicates that the La _{1− x} Nd _x AlO ₃ alloys may possess half-metallic (HM) behaviors when doped with Nd of a finite density of states at the Fermi level ( E _F). The direct and indirect band gaps are studied each as a function of x which is the concentration of Nd-doped LaAlO ₃. The calculated magnetic moments in the La _{1− x} Nd _x AlO ₃ alloys are found to a...

Structural, electronic and optical properties of the zinc-blende Ga _{1− x} Al _x P ternary alloys with their ordered AlP and GaP binary compounds have been investigated, using the full potential linearized augmented plane wave method in conjunction with the density functional theory. The total energies are carried out to calculate the lattice constant, bulk modulus and its pressure derivative of the zinc-blende AlP, GaP binary compounds and their corresponding ternary Ga _{1− x} Al _x P solid solutions for the compositions ( x = 0.25, 0.50 and 0.75). The band gap energies and the optical properties of these materials are investigated at normal pressure condition as well as under high pressure levels. The estimated results obtained from this work are justified, discussed and compared with the experimental data and other available theoretical works.

The increase in energy demands is leading to growing interest in new thermoelectric inorganic materials, such as the chalcogenides. The recently synthesized quaternary chalcogenide, Tl ₂PbXY ₄ (X = Zr, Hf and Y = S, Se), compounds were investigated using the full potential linear augmented plane wave method based on density functional theory. We used the generalized gradient approximation plus the optimized effective Hubbard parameter U to treat the exchange correlation. The existence of heavy metals (Tl, Pb and Hf) required the application of relativistic spin–orbit coupling via a second variational procedure. Tl ₂PbHfS ₄, Tl ₂PbHfSe ₄, Tl ₂PbZrS ₄ and Tl ₂PbZrSe ₄ compounds were found to be semiconductors with indirect band gaps of 0.911, 0.659, 0.983 and 0.529 eV, respectively. The types of carriers and electrical transport properties of Tl ₂PbXY ₄ (X = Zr, H...

The electronic and magnetic properties of EuAlO ₃ are calculated by first-principles full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). The exchange and correlation potential is treated with different approximations: mBJ and GGA +  U. Coulomb repulsion ( U) has been calculated using super-cell calculations for EuAlO ₃. The GGA +  U calculations reveal an indirect band gap of 4.6 eV for EuAlO ₃ in the spin down channel supporting the half metallic (HM) nature of the system. An effective integral magnetic moment also supported the HM nature of EuAlO ₃.

First-principles spin-polarized density functional theory (DFT) investigations of the structural, electronic, magnetic, and thermodynamics characteristics of the half-Heusler, CoMnTe and RuMnTe compounds are carried out. Calculations are accomplished within a state of the art full-potential (FP) linearized ( L) augmented plane wave plus a local orbital (APW + lo) computational approach framed within DFT. The generalized gradient approximation (GGA) parameterized by Perdew, Burke, and Ernzerhof (PBE) is implemented as an exchange correlation functional as a part of the total energy calculation. From the analysis of the calculated electronic band structure as well as the density of states for both compounds, a strong hybridization between d states of the higher valent transition metal (TM) atoms (Co, Ru) and lower valent TM atoms of (Mn) is observed. Furthermore, total and partial density of states (PDOS) of the ground state and the results of spin magnetic moments reveal th...