Interplay of Eu-4f Magnetism and Spin-Dependent Transport in Zintl Compounds Eu(ZnX) ₂ (X = P, As)

We present a first-principles investigation of the electronic structure, magnetic ordering, spin-dependent transport, and thermoelectric properties of Eu-based Zintl compounds Eu(ZnX) 2 (X = P, As) using the full-potential linearized augmented plane-wave (FP-LAPW) method within density functional theory. Both compounds crystallize in the tetragonal ThCr 2 Si 2 -type structure and exhibit negative formation energies, confirming their thermodynamic stability. Electronic structure calculations employing the modified Becke-Johnson potential reveal metallic behavior in both spin channels, with dominant contributions from localized Eu-4f states near the Fermi level, leading to pronounced spin polarization. Total-energy analysis supports a ferromagnetic ground state for both systems. Spin-resolved transport calculations indicate notable spin-dependent Seebeck coefficients, with Eu(ZnP) 2 showing enhanced thermoelectric response at elevated temperatures, suggesting potential for spin-caloritronic applications. Elastic property analysis indicates that Eu(ZnP) 2 exhibits comparatively ductile behavior, whereas Eu(ZnAs) 2 is mechanically stiffer and more brittle. The combined electronic, magnetic, and transport characteristics highlight the role of Eu-4f states in governing multifunctional behavior in Eu(ZnX) 2 compounds.