Multifunctional Properties of CrFeScPb and CrFeYPb Heusler Compounds: A DFT-Based Perspective

We report a first-principles study of the structural, electronic, magnetic, mechanical, thermodynamic, and optical properties of the quaternary Heusler alloys CrFeScPb and CrFeYPb using Density Functional Theory (DFT) with a modified Becke–Johnson (mBJ) potential. Both compounds are half-metallic with metallic behavior in the spin-up channel and semiconducting behavior in the spin-down channel with indirect gaps of 0.453 eV (CrFeScPb) and 0.409 eV (CrFeYPb). Their spinel-type magnetic moments and full spin polarization demonstrate a spintronic potential. Mechanical investigations determine CrFeScPb to be hard and brittle, while CrFeYPb is ductile. Their thermodynamic stability is realized under extensive temperature and pressure ranges, with a higher thermal resistance of CrFeScPb and higher compressibility of CrFeYPb. Stronger UV–visible absorption observed in the optical findings, particularly for CrFeYPb, demotes optoelectronics and magneto-optics applications. These findings highlight the multifunctionality potential of these alloys for spintronic, thermoelectric, and photonic devices.