First-principles calculations of structural, electronic, elastic, and thermal properties of phase M2CdC (M = Sc, V, and Nb)

Using the first-principle methods based on the density functional theory, in order to study structural, elastic, and electronic properties of MAX phases M2CdC with M = (Sc, V, and Nb). The calculated formation energies revealed that these compounds are thermodynamically stable in the hexagonal MAX phase. The stability is affirmed by the elastic constants and the conditions of the mechanical stability criterion. The calculated electron band structures and the density of states imply that the chemical bond in three compounds are a combination of covalent, ionic, and metallic nature. The main factors governing the electronic properties are the hybrid states M -d, Cd-p, and C -p, and the bond (p -d) stabilizes the structure. Fermi's surface characteristics have been studied for the first time. Based on the total energy, we conclude that as continue to increase Sc-V, Nb, the compressibility modulus decreases. At the same time, it gives a stabilization of the hexagonal structure and increases the metal support.