Ab initio investigations of the structure-stability, mechanical, electronic, thermodynamic and optical properties of Ti2FeAs Heusler alloy

Abstract

In this study, we employed density functional theory coupled with the full-potential linearized augmented plane-wave method (FP-LAPW) to investigate the structural, electronic, and magnetic properties of the Ti₂FeAs alloy adopting the Hg₂CuTi-type structure. Our findings demonstrate that all the examined structures exhibit ferromagnetic (FM) behaviour. By conducting electronic band structure calculations, we observed an energy gap of 0.739 eV for Ti₂FeAs in the spin-down state and metallic intersections at the Fermi level in the spin-up state. These results suggest the half-metallic (HM) nature of Ti₂FeAs, where the Ti-d and Fe-d electronic states play a significant role near the Fermi level. Additionally, the obtained total magnetic moments are consistent with the Slater–Pauling rule (M_tot = Z_tot − 18), indicating 100% spin polarization for these compounds. To explore their optical properties, we employed the dielectric function to compute various optical parameters, including absorption spectra, energy-loss spectra, refractive index, reflectivity, and conductivity. Furthermore, various thermodynamic parameters were evaluated at different temperatures and pressures. The results obtained from the elastic parameters reveal the anisotropic and ductile nature of the Ti₂FeAs compound. These findings suggest that Ti₂FeAs has potential applications in temperature-tolerant devices and optoelectronic devices as a UV absorber.