Determination of Spin-Based Half-Metallic, Mechanical, Magnetic and Thermodynamic Properties of Quaternary Half-Heuslers Zrcofex (X=si, as and Ge) Using First-Principle Calculations.

The First Principle Density Functional Theory (DFT) method was used to investigate the half-metallic character, magnetic and thermodynamic properties of ZrCoFeX (X=Si, As and Ge). Electronic and magnetic properties such as Band structures, Densities of states, and magnetic moments, spin – polarization indices of each alloy are also determined to confirm half-metallicity and ferromagnetism. Thermodynamic properties are also computed using Quantum Espresso-based Thermoₚw code. The half-metallic band gaps of ZrCoFeAs, ZrCoFeSi and ZrCoFeGe are 0. 206eV, 0. 205eV and 0. 203eV respectively. The spin-up channels in the electronic band structures of ZrCoFeX (X=Si, As and Ge) have indirect energy band gap, indicating that they exhibit half-metallic character. The quaternary Heuslers are accurately ferromagnetic as they all obey Slater Paulin’s rule having magnetic moments of 4. 0215μB, 4. 1573μB and 4. 6711μB respectively and are 100% spin-polarized. The Curie Temperatures Tc of ZrCoFeX (X=Si, As and Ge) are 526K, 859K and 963K respectively. However, only ZrCoFeAs, and ZrCoFeGe preserved their mechanical stability after undergoing stress-strain test. This makes them preferable candidates in the field of semiconductor physics. The heat capacities of ZrCoFeX (X=Si, As and Ge) obey Dulong-petit law showing that they have good thermal applications in optoelectronic devices e. g. Photo diodes, Solar cells etc.