In the purpose of exploring new Heusler alloys with different magnetic applications, we have employed first principles calculations method within density functional theory. After checking the structural stability of X2YZ Heusler alloys (X = Fe, Co; Y =Zr, Mo and Z = Ge, Sb), we found that Cu2MnAl type structure is more favorable for most compounds except for X2MoGe and Co2MoSb, were the Hg2CuTi structure is energetically more stable. The trends in magnetic and electronic structures can be predicted by the structure types as well as the different kinds of hybridizations between the constituents. Among the two series only two compounds were identified to be true half metals with potential applications in spintronic devices. While one compound was classified as a nonmagnetic semiconductor with a small band gap. For the rest of materials, we found that the metallic behavior is dominant. These materials show possible interesting features in technical applications as well. The effect of distortion on the magnetic properties of Co2ZrGe and Fe2ZrSb showed that the half metallic character was preserved within a moderate range of volume changes, which makes it possible to grow these materials as thin films with modern techniques.

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Since they have become indispensable in various technological applications and a powerfulsource for generating energy in thermoelectric devices, Lithium-based alloys symbolize the topicof many experimental and theoretical reports. Hence, LiAlX(X = C, Si, Ge, Sn) materials representthe main research in this study. Different interesting properties such as the effect of pressure onthe band gap as well as the elastic parameters and the thermoelectric efficiency of these materialswere investigated using the full potential linearized augmented plane wave (FP-LAPW) method.LiAlX alloys were found to be semiconducting with indirect band gaps. When studying themechanical properties, we found that LiAlC alloy is stable against a wide range of pressurechanges (90 GPa), while the rest three systems preserve their mechanical stability in a moderaterespectively range of 40, 50 and 30 GPa, respectively. The semiconducting band gap for eachpossible transition have been calculated in a range of different pressures using both GGA andmBJ-GGA approximations. The results ended up revealing a decaying trend of the indirect gapalong Г-X direction with the increase of pressure. High values of the power factor were achievedand a large figure of merit (almost 0.7 for all systems) was calculated at 600K, which makesthese Li-based alloys very auspicious in the thermoelectric field applications.

The structural, elastic, mechanical, magneto-electronic, and thermoelectric properties of Sr2TiCoO6 double perovskite oxide have been studied within the framework of density functional theory. The FP-LAPW method within the (GGA) and (mBJ) approximations is chosen in the computational approach. This alloy crystallizes in cubic structure with the ferromagnetic phase. The computed lattice constant was found to agree with the available experimental results. This compound shows the half-metallic ferromagnetic properties. A value of 1 µB is found for the total magnetic moment with an important contribution from Co atoms. The elastic parameters reveal that Sr2TiCoO6 as being super hard and brittle. We calculated the thermoelectric properties of Sr2TiCoO6 using the Boltzmann transport equations within the DFT in a temperature range from 100 to 1000 K. The transport parameters like Seebeck coefficient, electrical thermal conductivity and the merit factor, have been put together to establish their thermoelectric response. The figure of merit value is between [0.71-0.99] indicating that our compound is a good candidate for thermoelectric applications at high and low temperatures.

Using first-principles calculations based on density functional theory, structural, elastic, electronic and thermoelectric properties of laves phase LaCo2 intermetallic compound with prototype MgCu2 are stated in this paper. The optimized lattice constant by structural optimization is found to be rationally compatible with the experimental lattice constant.  The Generalized Gradient Approximation (GGA) +Hubbard model was incorporated to evaluate the exact electronic structure. Elastic properties such as, elastic constants, bulk modulus B, shear modulus G, Young’s modulus E, and Poisson ratio ν have been determined using the Voigt–Reuss– Hill approximation. The ductility nature appears in both values of Cauchy pressure and Pugh’s ratio. The band structures and the Cauchy pressure show that the material behaves as metallic. In addition, semi-classical Boltzmann theory is used to verify the applicability of the material for thermoelectric applications. Calculations depict that the spin-up/down transport coefficients are temperature-dependent. It has been found that LaCo2 has a high Seebeck coefficient and therefore a large power factor.