A systematic first-principles investigation of the structural, electronic, mechanical, optical, and thermodynamic properties of Half-Heusler ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) for spintronics and optoelectronics applications.

This paper is the first to look at the structural, electronic, mechanical, optical, and thermodynamic properties of the ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) half-Heusler (HH) using DFT based first principles method. The lattice parameters that we have calculated are very similar to those obtained in prior investigations with theoretical and experimental data. The positive phonon dispersion curve confirm the dynamical stability of ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn). The electronic band structure and DOS confirmed that the studied materials ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) are direct band gap semiconductors. The investigation also determined significant constants, including dielectric function, absorption, conductivity, reflectivity, refractive index, and loss function. These optical observations unveiled our compounds potential utilization in various electronic and optoelectronic device applications. The elastic constants were used to fulfill the Born criteria, confirming the mechanical stability and ductility of the solids ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn). The calculated elastic modulus revealed that our studied compounds are elastically anisotropic. Moreover, ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) has a very low minimum thermal conductivity (Kmin), and a low Debye temperature (θD), which indicating their appropriateness for utilization in thermal barrier coating (TBC) applications. The Helmholtz free energy (F), internal energy (E), entropy (S), and specific heat capacity (Cv) are determined by calculations derived from the phonon density of states.

Perovskite-structure TlBO3 (B = Cr, Mn) for thermomechanical and optoelectronic applications: an investigation via a DFT scheme.

First-principles-based DFT calculations have been carried out to analyze the structural, mechanical, elastic anisotropic, Vickers hardness, electronic, optical, and thermodynamic properties of TlBO3 (B = Cr, Mn) for the first time. We determined the lattice parameters, which are in good agreement with the previous results. The Born criteria was ensured by the elastic constants, which also confirms the ductility of the solid. The elastic constants were also used to evaluate and analyze some related physical properties. The values of Vickers hardness were calculated to determine the hardness and relative application of both TlCrO3 and TlMnO3. Though the metallic characteristics were evaluated via the investigation of the electronic band structure and density of states, both TlCrO3 and TlMnO3 reveal semiconducting behavior under spin-orbit polarization with up-spin and down-spin configurations. Significant constants such as absorption, conductivity, reflectivity, dielectric, loss function, and refractive index were also considered and determined without spin and with spin. As a result, various possible electronic, optical, and optoelectronic applications were predicted. TlBO3 (B = Cr, Mn) was also found to be reliable for thermal barrier coating (TBC) as indicated by the evaluated values of thermal conductivity and Debye temperature.