First-Principles Study of the Structural, Electronic, Magnetic, Elastic, and Optical Properties of CoFeZrGe Quaternary Heusler Alloy

This study focuses on the quaternary Heusler alloy CoFeZrGe, explored through first-principles calculations to evaluate its potential in spintronic and optoelectronic applications. Heusler alloys attract significant interest due to their diverse electronic and magnetic characteristics, particularly their capacity to exhibit half-metallic ferromagnetism, a property crucial for high-performance spintronic devices. Here, the structural, electronic, magnetic, mechanical, and optical properties of CoFeZrGe are systematically investigated.

Computations were carried out within the framework of density functional theory (DFT) using the full-potential linearized augmented plane wave (FP-LAPW) method implemented in WIEN2k. Three atomic configurations compatible with the F-43m space group (Y1, Y2, and Y3) were considered, with structural optimization identifying the Y1 arrangement as the lowest energy configuration. The electronic structure was analyzed using both the generalized gradient approximation (GGA-PBE) and the modified Becke–Johnson (TB-mBJ) potential.

The findings reveal that CoFeZrGe possesses half-metallic ferromagnetism, featuring an indirect minority-spin band gap of 0.48 eV (GGA) and 1.27 eV (TB-mBJ). The material exhibits a total magnetic moment of 1 μB per formula unit, consistent with the Slater–Pauling rule. Calculated elastic constants verify mechanical stability and indicate ductility, supported by favorable values of bulk modulus, shear modulus, Poisson’s ratio, and Pugh’s ratio. Optical results, including the dielectric function, absorption coefficient, and energy loss spectra, highlight pronounced interband transitions and strong absorption across the visible and ultraviolet regions.

Overall, CoFeZrGe demonstrates a combination of stable half-metallicity, mechanical robustness, and excellent optical response, making it a strong candidate for future spintronic and optoelectronic technologies.