In this study, we have investigated the structural, electronic, and elastic properties of the M2CdC (M = Ta, Zr, and Hf) MAX phases, using the first-principle methods based on the density functional theory. The calculated formation energies revealed that these compounds are thermodynamically stable in the hexagonal MAX phase. The stability is confirmed by the elastic constants and the conditions of mechanical stability criterion. Also, we have determined the bulk and shear modules of the Young modulus and the Poisson coefficient. The band structures indicate that the three materials are electrically conductive. The chemical bond in M2CdC is covalent-ionic in nature with the presence of metallic character. For the density of states the hybridization peak between M d and C p occurs in the lower energy range. We have found that there is no gap for these materials due to the existence of a maximum peak of DOS around Fermi level.

In this paper, we have investigated the structural, elastic, electronic, and magnetic properties of Rh2CrGe full-Heusler alloy in the regular type (Cu2MnAl, prototype L21) phase by using the first-principle methods of density functional theory with local spin-density approximation. We have found that Rh2CrGe is stable in the ferromagnetic configuration. This result is confirmed by the calculated cohesive energies. The stability criteria show that Rh2CrGe is mechanically stable in L21 structure. The spin-polarized electronic structures depicted a metallic character. The calculated total magnetic moment of 3.78 µB is not in agreement to the value of 4 µB of the Slater-Pauling rule. Therefore the Rh2CrGe full-Heusler alloy is metallic ferromagnet in nature.

In this study, we have investigated the structural, electronic, and elastic properties of a new series of Os2YAl, (Y=Sc, Ti, V) alloys called "Full Heusler", based on the Wien2k code using the functional density theory (DFT). The exchange and correlation energy are evaluated as part of the LDA approximation.  The results showed that Os2VAl was more stable and harder than Os2ScAl, and Os2TiAl. The electronic band structures and density of states (DOS) of the compounds indicate that they are metallic because there is no bandgap in these three materials these results have been shown by three approaches (LDA, TB-mBJ, and SOC). Near the Fermi level, the energy is mainly occupied by the Os-5d and Sc, Ti, V-3d electrons. According to the results of the second-order elastic constants, these compounds met Born's criteria for mechanical stability. The elastic properties indicate that our compounds are ductile, anisotropic, and rigid. All the calculations and the data were compared with the results obtained with different methods in terms of its mechanical and electronic behavior, Os2VAl was found to have better physical properties than Os2ScAl, and Os2TiAl.

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In this study, we have employed the first-principle methods based on density functional theory to investigate the structural, electronic and optical properties of Al0.50Ga0.50NxSb1-x in zincblende structure. The exchange and correlation potential is described by the generalized gradient approximation of Perdew, Burke and Ernzerhof (GGA-PBEsol) coupled with TB-mBJ approaches. The studied structures shows that all structures are semiconductors and have a direct bandgap except Al0.50Ga0.50N0.25Sb0.75 which has a semi-metallic behavior. The optical properties such as refractive index, extinction coefficient and optical conductivity are discussed in detail. Our result shows these materials are considered as promising materials for optoelectronic applications in the visible and infrared region. To our knowledge this is the first time that a study has been done on this alloy and we would like it to serve as a reference for the next studies.