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In this investigation, we employ density functional theory with the generalized gradient approximation of Wu–Cohen and the modified Beck–Johnson approach. Our focus is on examining the structural, electronic and thermodynamic properties of ternary chalcopyrite CdXP2 (X: Si and Sn) compounds. Our computed results of ternary structures for structural properties, for instance, tetragonal distortion, equilibrium lattice constants and bond lengths, show good agreement with the available results of the experimental and theoretical calculations. Our calculated positive results of cohesive energy and negative values of the formation energies of the title materials show their thermodynamic stability as well as highlight their possible experimental fabrication at these concentrations. From band structure calculations, it is found that the energy bandgap is of direct nature at Γ–Γ symmetry points for both ternary and quaternary alloys; however, the width of the bandgap is found to be decreased with increasing Sn concentration in the CdSi1–xSnxP2 alloys. Moreover, thermodynamic properties using the quasi-harmonic Debye model are also computed. Our study provides a platform for further experimental and theoretical investigations to expose the potential of these materials for their applications. [ABSTRACT FROM AUTHOR]

We have simulated different physical properties of Pb1−xSrxTe semiconductors, using theAb-initiofull potential augmented plane wave (FP-LAPW) method. The two commonly used exchange potentials viz., PBE-GGA and WC-GGA are used along with the most recently developed modified Becke and Johnson (mBJ) potential to study the electronic and optical properties. In this study, we have observed an increase in band gap values as well as the lattice parameter with increasing the concentration of Sr atoms in Pb1−xSrxTe alloys while the bulk modulus and the refractive index have reverse effect. The microscopic origin of the band gap bowing is explained using the approach of Zunger and co-workers. At ambient conditions (p = 0,T = 0), the calculations indicate that Pb1−xSrxTe is a direct band gap semiconductor R–R withx = 0.125, 0.25, 0.375, 0.5, 0.625, 0.75 and 0.875. The refractive indices are also calculated using the FP-LAPW method and the models of Moss, Ravindra and the Herve–Vandame. The obtained results are in consistent with the previous available data. To study the thermal effects, the temperature effect on the lattice parameters, thermal expansions, heat capacities the quasi-harmonic Debye model is applied. The Debye temperature is determined from the non-equilibrium Gibbs function. [ABSTRACT FROM PUBLISHER]

In this work, a series of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) with several weight percentages (0.1, 0.4, 0.8, and 1.0 wt.%) were synthesized by catalytic chemical vapor deposition (CCVD) technique. The N-MWCNTs were first characterized and then dispersed in high-density polyethylene (HDPE) polymer matrix to form a nanocomposite. The HDPE/N-MWCNT nanocomposite films were prepared by melt mixing and hot pressing; a good dispersion in the matrix and a good N-MWCNT-polymer interfacial adhesion have been verified by scanning electron microscopy (SEM). Raman spectroscopy measurements have been performed on prepared samples to confirm the presence and nature of N-MWNTs in HDPE matrix. The X-ray diffraction (XRD) analysis demonstrated that the crystalline structure of HDPE matrix was not affected by the incorporation of the N-MWNTs.