Tunable magnetism and strong UV absorption in CrTiX (X = Ga, In) half-Heusler compounds: Insights from first-principles calculations

This work employs density functional theory (DFT) to explore the structural, electronic, elastic, optical, and magnetic properties of CrTiX (X[Formula: see text][Formula: see text][Formula: see text]Ga, In) half-Heusler compounds. The optimized lattice constants (6.11[Formula: see text]Å for CrTiGa and 6.40[Formula: see text]Å for CrTiIn) and Goldschmidt tolerance factors (0.97 for CrTiGa and 0.95 for CrTiIn) confirm structural stability with slight cubic distortion. Elastic constants fulfill Born–Huang stability criteria, indicating mechanical stability, with CrTiIn exhibiting higher stiffness. Poisson’s ratio suggests dominant metallic bonding, and moderate elastic anisotropy is observed in both materials. Electronic structure analysis reveals metallic behavior, primarily governed by Cr-3d and Ti-3d states. Optical studies show strong UV absorption, peaking at 2.5[Formula: see text]eV (CrTiGa) and 2.1[Formula: see text]eV (CrTiIn), along with moderate reflectivity and high dielectric constants favorable for optoelectronic and spintronic applications. Magnetic calculations show stronger spin polarization in CrTiIn (0.30188[Formula: see text][Formula: see text]) than in CrTiGa (0.11750[Formula: see text][Formula: see text]). These results highlight the potential of CrTiX compounds for next-generation functional materials.