This study comprehensively investigated the structural, elastic, electronic, magnetic and thermodynamic characteristics of the BeFeCd semi-Heusler alloy via density functional theory with the generalized gradient approximation. The alloy crystallizes in the F(43) ̅m space group, with Be, Cd and Fe atoms occupying the (0, 0, 0), (1/4, 1/4, 1/4) and (3/4, 3/4, 3/4) Wyckoff positions, respectively. Structural optimization yielded an equilibrium lattice parameter of 5.487 Å for the mechanically stable configuration. The calculated elastic constants (C11 = 195.48 GPa, C12 = 105.07 GPa, C44 = 16.44 GPa) satisfy the Born stability conditions, confirming the robustness of the crystal structure. The calculated Poisson's ratio (0.412), bulk modulus (135.21 GPa), shear modulus (24.99 GPa) and B/G ratio (5.41) suggest that the alloy combines metallic bonding characteristics with ductile mechanical behavior and has relatively low compressibility. Electronic band structure and density of states analyses revealed that the alloy possesses metallic conductivity dominated by Fe-3d electronic states. Magnetic calculations indicate a total magnetic moment of 2.2 μB per formula unit, suggesting ferromagnetic ordering. The thermodynamic properties evaluated through the Debye model, including vibrational energy, free energy, entropy and heat capacity, exhibit temperature-dependent trends that are consistent with those of typical semi-Heusler alloys. The Debye temperature was determined to be 266.242 K. Overall, these results suggest that BeFeCd is a mechanically stable, metallic and magnetically active semi-Heusler alloy with promising potential applications in spintronics and magnetoelectronics.
Erol Albayrak (Tue,) studied this question.