Search

The impact of pressure on structural parameters, electronic structure and magnetic properties in MoS2 bulk material has been investigated using spin-polarized full-potential linearized augmented plane wave method in the Tran-Blaha-modified Becke-Johnson gradient approximation approach. Our findings at zero pressure in MoS2 bulk material are usually dealing with the obtainable experimental input. With increasing pressure, the lattice parameters of MoS2 bulk material are reduced, the material of interest has tendency to a metallic character and the total magnetic moment is increased non-monotonically in both spin-up and spin-down conduits. The impact of pressure on structural properties is more important vs. c-axis than a-axis. [ABSTRACT FROM AUTHOR]

We report on structural properties, elastic constants, mechanical and dynamical stabilities, electronic band structure, and hydrogen storage applications of Mg2FeH6 at zero and high-pressure effects. The work has been realized within the full-potential linearized augmented plane wave method. At zero pressure, the material under study is stable and has a ductile nature. The electronic structure of the material of interest is determined to be X-X wide direct band gap semiconductor with an energy of 1.88 eV. The hydrogen storage capacity wt (%) and the hydrogen desorption temperature are reported as 5.473 and 625.47 K respectively. The Debye temperature ϴD is recorded as 698 K using the elastic constants and about 775 K using the Gibbs calculations. Under high-pressure effect up to 80 GPa, the semiconductor still be an X-X semiconductor with an energy gap of 3.91 eV. The Debye temperature ϴD increases monotonically up to about 1120 K at 80 GPa when using the calculated elastic constants whereas the desorption temperature decreases from 650 to 0 K by increasing pressure from 0 to about 87 GPa. [ABSTRACT FROM AUTHOR]

In the present work, we have investigated the structural, electronic and optical features of ZnS1−xOx graphene-like monolayer's for different x values compositions (0, 0.25, 0.5, 0.75 and 1) using the modified Becke–Johnson approach calculations within the framework of the density functional theory (DFT). The lattice parameter has been determined and found to deviate from Vegard's law for the ZnS1−xOx monolayer. The electronic band structure has been explored where the band gap energy has been found to be non-zero and direct in nature. This makes our material useful for optoelectronic devices. Besides, the optical spectra of the real and imaginary parts of the dielectric function along with the refractive index have all been addressed and found to be in good accordance with previous works reported for ZnS and ZnO monolayer's. [ABSTRACT FROM AUTHOR]

Using ab initio total energy based on density functional theory calculations, the phase transition, band structure, optical spectra and magnetic moment of MnO in the rock salt structure have been investigated. All studied quantities are discussed with respect to their dependence on pressure. Our results show a phase transition of MnO from the semiconducting rock salt to a metallic CsCl at pressure of 67.12 GPa. Applied pressure is found to play an important role in the modulation of optical properties. The optical absorption coefficient indicates that MnO more readily absorb photons under high pressure. The total magnetic moment for rock salt MnO at zero pressure agrees reasonably well with those reported in the literature and decreases monotonously with increasing pressure. [ABSTRACT FROM AUTHOR]

We report on spin-polarized first-principles calculations within the generalized gradient approximation of structural parameters, dielectric function spectra, and total magnetic moment of hypothetical zinc-blende Zn1−xMoxTe. Good accord is generally obtained between our results and those available from the literature. A close inspection of the composition dependence of the features of interest shows that the lattice parameter violates the Vegard's law, the magnetism and character of the material in question depend strongly on the composition x and the spin channel, the optical response function shifts toward either higher or lower photon energies (depending on x) and the total magnetic moment increases with increasing the Mo concentration. [ABSTRACT FROM AUTHOR]

The present contribution reports on the electronic structure and optical properties of the polyaniline polymer material. The calculations are performed using ab initio total energy calculations within the full-potential linearized augmented plane wave method in the framework of the density functional theory. The generalized gradient approximation is used to treat the effects of exchange and correlation. The fundamental band-gap energy and static and high-frequency dielectric constants of the polymer of interest are predicted. The optical spectra against the photon incident energy along both the x- and z-axis are presented and examined. [ABSTRACT FROM AUTHOR]

Ab initio calculations based on density functional theory have been performed using the full-potential augmented-plane-wave method so as to investigate the composition dependence of the electronic structure and fundamental properties of hypothetical zinc-blende Cd1-xCoxTe magnetic semiconductor alloys at low Co concentrations. To treat the exchange and correlation energies, the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof has been used. In addition, the modified Becke-Johnson exchange potential with the GGA approach is used for the band structure providing high accuracy. It is found that the addition of a small amount of Co atoms in the Cd1-xCoxTe makes the latter less compressible, ferromagnetic and exhibiting a half metallic character. Besides, the composition dependence of the real and imaginary parts of the dielectric function has been examined and discussed. The information derived from the present study may be useful for spintronics technological applications. [ABSTRACT FROM AUTHOR]

The impact of pressure on structural parameters, electronic structure and magnetic properties in MoS2 bulk material has been investigated using spin-polarized full-potential linearized augmented plane wave method in the Tran-Blaha-modified Becke-Johnson gradient approximation approach. Our findings at zero pressure in MoS2 bulk material are usually dealing with the obtainable experimental input. With increasing pressure, the lattice parameters of MoS2 bulk material are reduced, the material of interest has tendency to a metallic character and the total magnetic moment is increased non-monotonically in both spin-up and spin-down conduits. The impact of pressure on structural properties is more important vs. c-axis than a-axis. [ABSTRACT FROM AUTHOR]

The electron energy levels, direct energy band gaps, electron and hole effective masses as well as the transverse effective charge of InAs spherically shaped quantum dots have been studied as a function of the quantum dot radius considered as varying from 1 to 10 nm. The direct energy band-gap as well as the electron and heavy hole effective masses decrease non-linearly with increasing the quantum dot radius. Nevertheless, the transverse effective charge is found to increase with increasing the quantum dot radius. It is concluded that the quantum confinement has a strong influence on all the studied physical quantities for quantum dot radius below 6 nm. The results of the present contribution show that more opportunities can be offered to tailor desired optoelectronic properties surpassing those presented by bulk InAs materials. [ABSTRACT FROM AUTHOR]

In the present contribution a ZnO/CdS/CZTS structure with new thicknesses of the different layers has been proposed using solar cell capacitance simulator. The objective of this study is the improvement of the device efficiency while varying the thickness of the various layers and the CZTS system energy band-gap. Our results showed that cells with optimal values of thicknesses of 0.1, 0.02 and 1 µm for ZnO window layer, CdS buffer layer and CZTS absorber layer, respectively give conversion efficiency of 23.56%. Furthermore, the higher performance of these cells is obtained for a CZTS band-gap energy of about 1.45 eV. The obtained conversion efficiency is comparable to those previously reported in the literature. [ABSTRACT FROM AUTHOR]