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 Thermo_pw 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.