First‐Principles Study of the Spintronic Potential of the Rare‐Earth‐Based Half‐Heusler Compound FeCeBi

Abstract Systematic theoretical research of the half‐Heusler compound FeCeBi is carried out using first‐principles calculations on density functional theory (DFT) here. Three candidate crystal structures are studied, of which it is found that the ground‐state most stable configuration is the α‐phase in the ferromagnetic (FM) state. Electronic band structure computations verify that FeCeBi is an ideal half‐metal with a semiconducting gap in the spin‐up channel and metallic behavior in the spin‐down channel, and hence, it is highly promising for spintronic devices. Elastic properties such as elastic constants (C 11 , C 12 , and C 44 ) confirmed mechanical stability based on Born–Huang criteria. Other mechanical indicators, such as the ratio B/G and Poisson's ratio, indicate a good balance of ductility and stiffness. Additionally, the electronic structure is determined to be structurally deformed sensitive; when compressed, the bandgap expands, while it reduces with dilatation. This tunability makes it easy to adapt FeCeBi to specific applications. Optical study reveals spin‐dependent effects, further confirming the compound's asymmetric half‐metallic character. Generally, the results demonstrate that FeCeBi is a very suitable material candidate for future spintronic and multifunctional device technologies.