Ferromagnetism study in doped <i>LiMgAs</i> _{1− <i>x</i>} <i>W</i> _<i>x</i> half-Heusler: insights from KKR-CPA calculations

Abstract

Abstract The electronic and magnetic properties of the doped diluted magnetic semiconductor LiMgAs have been systematically investigated, with a specific focus on the effects of tungsten (W) doping. This study employs a combination of the Korringa-Kohn-Rostoker Coherent Potential Approximation (KKR-CPA), first-principles calculations within the framework of the Generalized Gradient Approximation (GGA), and the parametrization method of Pedrew Burke and Ernzerhof (PBE) is used. Our findings reveal that the incorporation of W into the LiMgAs host lattice significantly enhances the total magnetic moment of the doped system. At a doping concentration of 12%, the system’s total magnetic moment is −0.3654 μ B, with W contributing −2.4532 μ B. Additionally, the magnetic moment of W varies between −2.430 μ B and −2.530 μ B for all doping percentages. This magnetic moment in LiMgAs 1− x W x arises primarily from spin polarization at the Fermi level ( E F ). Consequently, at concentrations below 12%, polarization values at the Fermi reached more than 97%. Half-metallic ferromagnetic behavior is observed for all dopant concentrations. Moreover, the ferromagnetic state is stable due to the double exchange mechanism. Notably, the doped compound exhibits a high Curie temperature (Tc), reaching a maximum value of approximately 560 °K at a doping concentration of 12%, indicating robust magnetic behavior. The observed double exchange interaction, responsible for the short-range magnetic ordering, is facilitated by p–d orbital hybridization. Thanks to this research, we have been able to gain a comprehensive understanding of how strain and W doping can be used to tailor the electronic and magnetic properties of LiMgAs compounds. Consequently, W-doping in LiMgAs provides a promising pathway for the design and development of novel spintronic materials with desirable magnetic characteristics.